JPH11109994A - Device and method for encoding musical sound and storage medium recording musical sound encoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality and a compression rate by resetting a quantization width of a parameter of a frequency band based on information related to the quantization error of the parameter of the frequency band from a quantization part and outputting it to the quantization part. SOLUTION: The quantization part 16 calculates the quantization encoding data from the parameters of respective frequencies calculated by a time-frequency conversion part 12 based on precision of quantization bits in respective frequency components for quantization calculated by an auditory sense model calculation part 18. A minimum error selection part 17 selects one with less errors between error amounts of quantization of a frequency parameter pair affecting each other from the error amount of the quantization of the parameters of respective frequencies inputted from the quantization part 16 to output quantization error information to the quantization part 16. Then, the quantization part 16 sets again the quantization encoding data such as respective frequency components, the size of the parameter of a band, quantization precision, the quantization data, etc., based on the selected quantization error information to output them to an encoding line generation part 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tone encoding apparatus, a tone encoding method, and a recording medium storing a tone encoding program for analyzing, compressing and encoding an arbitrary input tone.

[0002]

2. Description of the Related Art A musical sound encoding / decoding apparatus which encodes musical sounds 1) has a high reproducibility after encoding and reproduction.
There is a demand for 2) a system with a small amount of processing and 3) a system with a high compression ratio. For this reason, when compressing a musical tone, the musical tone data is converted from the time domain to the frequency domain, and components in a frequency band not used in the frequency domain are not transmitted, and at the same time, mainly 1) simultaneous masking, 2 3.) A high compression rate is realized by limiting the transmission bit width in each frequency band based on the model of the minimum audibility.

[0003] As one method of conversion from the time domain to the frequency domain, there is a method using sub-band coding (SBC). This method allows a signal to pass through only a desired frequency band through a band-pass filter,
It is divided into frequency bands. At this time, downsampling is performed to reduce the amount of calculation and the amount of data, but aliasing occurs due to the influence of the side rope of the filter. In order to minimize the effect of aliasing, the amount of calculation is large, but it is necessary to construct a high-order filter. In order to solve this problem, many methods have been adopted to construct a QMF filter and remove the influence of the aliasing at the time of synthesis.

As a general method for converting from the time domain to the frequency domain, there is a method using transform coding (TFC) such as MDCT. This TF
Combine C and SBC to check the continuity of the signal in each frequency band. If stationary, increase the analysis window to increase the frequency resolution, and if non-stationary, shorten the analysis window to increase the time resolution. As a result, tone encoding with higher compression ratio and good reproducibility is realized.

[0005] As a typical tone compression method combining SBC and TFC, the ATRAC system used in MD and the Layer 3 of MPEG1 and MPEG2 are well known. MPEG Layer 3 (JIS standard)
X4323 and ISO / IEC11172-3), a QMF filter is used for SBC, and then TF
The musical tone is encoded and decoded using the MDCT analysis for C. Here, the configuration of the aliasing distortion reducer for solving the problem that the effects of aliasing cannot be sufficiently removed due to the quantization error at the time of encoding is shown. By using this configuration, it is possible to prevent the adverse effect of the QMF filter to some extent. It is possible.

FIG. 6 is a block diagram schematically showing a configuration of a conventional tone compression encoding apparatus. The musical sound encoding device shown in FIG. 6 includes a musical sound input unit 10 ', a frequency band division (QMF filter) unit 11', a time-frequency conversion unit 12 ', a quantization unit 16', an auditory model calculation unit 18 ', and a coded sequence. Generator 1
9 '. Hereinafter, the operation of the above-described musical tone encoding components will be described. First, the musical sound input unit 10 'inputs a musical sound, cuts out a musical sound waveform in analysis frame units, and outputs it to a frequency band dividing (QMF filter) unit 11' and an auditory model calculating unit 18 '.

Frequency band division (QMF filter) section 1
1 'represents the tone waveform output from the tone input unit 10' as Q
By passing only a desired frequency band through an MF filter, the data is divided into several pieces of time waveform data including only a specific frequency band, down-sampled and subjected to sampling conversion, and then the time-frequency conversion unit 1
Output to 2 '. The time-frequency conversion unit 12 'converts time waveform data including only a specific frequency band divided into several parts into frequency-domain parameters for each frequency band by using a method such as MDCT. Transformation part 16 '
Output to

[0008] The auditory model calculating section 18 'is provided with the musical sound input section 1
The tone waveform output from 0 'is subjected to frequency analysis using FFT or the like, and the precision of quantization bits in a frequency band for quantization is determined in accordance with an auditory model such as simultaneous masking and minimum audibility. Output to the unit 16 '. The quantization unit 16 ′ converts the frequency of each frequency converted by the time-frequency conversion unit 12 ′ based on the precision of the quantization bit in each frequency band for quantization calculated by the auditory model calculation unit 18 ′. The precision of the feature parameter of the region is cut off, and the quantized coded data such as the magnitude of the parameter of each frequency, the quantization precision, and the quantized data are output to the coded sequence generation unit 19 '.

Finally, a coded sequence generator 19 'transmits / accumulates quantized coded data such as parameter size, quantization accuracy, and quantized data of each frequency generated by the musical sound coder 16'. Then, it is converted into a coded sequence so as to increase the compression rate, and transmitted / stored by the coded sequence output unit 20 '. Here, a frequency band division unit (QMF filter) 1
1 ', a time-frequency conversion unit 12', a quantization unit 16 ', a coded sequence generation unit 19', and components of the auditory model calculation unit 18 '(portions surrounded by dotted lines in FIG. 4) are a coding control unit 21. ′ Can be used for control. In this case, it is possible to configure the encoding control unit 21 'with a computer, and realize the components in the range surrounded by the dotted line in FIG. 4 by a program.

[0010]

By using a QMF filter, it is possible in principle to completely eliminate aliasing components during synthesis. However, since the amount of data is reduced by performing rough quantization in order to increase the compression rate during encoding, aliasing components cannot be reduced sufficiently during synthesis, and the quantization error is perceptually perceived. There was a problem.

On the other hand, the MPEG Layer
The aliasing distortion reducer of No. 3 attempts to solve the problem by removing aliasing from the frequency component (MDCT coefficient) calculated by performing the MDCT analysis. In this case, since the QMF filter is used at the time of synthesis, the aliasing component is estimated, the frequency component (MDCT coefficient) added to the frequency component is synthesized, and then the time component is converted. However, since quantization is performed at the time of encoding, the frequency component (MD
There is a problem that the quantization error of the (CT coefficient) may be audibly perceptible.

An object of the present invention is to reduce the influence of the aliasing described above to a practically sufficient level, that is, to such an extent that it cannot be discriminated aurally. For this purpose, the magnitude of quantization may be determined to such an accuracy that aliasing components cannot be discriminated audibly, assuming that the frequency data pairs that influence each other include an aliasing component.

The method for solving this problem also takes into account quantization errors of frequency components that affect each other as aliasing distortion.
That is, both quantization methods are determined so as to adopt a smaller error so that both quantization errors become the same. In this case, compared with Layer 3 of MPEG, it is not necessary to estimate and reduce aliasing distortion at the time of encoding, and it is not necessary to estimate and add aliasing distortion at the time of decoding, thereby simplifying the processing configuration.

In order to further increase the compression ratio, it is possible to estimate the aliasing error from the quantization error of the frequency component. The quantization error of the frequency component may be determined so that the quantization error of the frequency component cannot be discriminated aurally. In this case, MPEG
As compared with Layer 3 of the above, the aliasing distortion may be estimated and reduced at the time of encoding as in the previous case, or the aliasing distortion may be estimated at the time of decoding and not added. Also, MPEG Layer
Similar to er3, the aliasing distortion may be estimated and reduced at the time of encoding, or the aliasing distortion may be estimated and added at the time of decoding.

[0015]

According to a first aspect of the present invention, there is provided a musical sound encoding apparatus according to the present invention, wherein a musical sound input unit for inputting a musical sound and a musical sound input to the musical sound input unit are provided. , A frequency band division unit that divides each of the frequency bands by using a QMF filter, an auditory model calculation unit that calculates a quantization width by using an auditory model, and time waveform data processed by the frequency band division unit in the frequency domain. A time-frequency conversion unit that converts the parameters into the following parameters; a quantization unit that quantizes the frequency domain parameters from the time-frequency conversion unit based on the quantization width from the auditory model calculation unit; And a coding generation unit for generating a coded sequence based on various information from the coding unit. Based on, resetting the quantization width of a frequency domain parameter, characterized in that a minimum error selector for outputting the quantization width to the quantization unit.

According to a second aspect of the present invention, in order to solve the above-mentioned problems, a tone input device for inputting a tone and a tone input to the tone input unit using a QMF filter. A frequency band dividing unit that divides the time waveform data processed by the frequency band dividing unit into a parameter in the frequency domain. −
A frequency conversion unit, a quantization unit that quantizes the frequency-domain parameters from the time-frequency conversion unit based on the quantization width from the auditory model calculation unit, and a variety of information from the quantization unit. Distortion encoding apparatus for producing a coded sequence by generating a coded sequence by using a frequency domain parameter from the quantization unit to calculate a quantization error of a folded distortion of a QMF filter. The estimation unit, based on the aliasing quantization error from the aliasing quantization error estimation unit, resets the quantization width of the parameter in the frequency domain, and outputs an error width determination unit that outputs the quantization width to the quantization unit. It is characterized by having been provided.

According to a third aspect of the present invention, in order to solve the above-mentioned problems, a tone input step of inputting a tone and a tone input to the tone input step are performed by QM.
A frequency band dividing step of dividing the frequency band using an F filter, a step of calculating an auditory model for calculating a quantization width using an auditory model, and a step of dividing the time waveform data processed in the frequency band dividing step into a frequency domain. A time-frequency conversion step of converting the parameters into parameters, a quantization step of quantizing the frequency-domain parameters from the time-frequency conversion step based on the quantization width from the auditory model calculation unit, and a quantization step. And a coding generation step of generating a coded sequence based on various information from the information processing apparatus. The method of performing tone coding, comprising the steps of: And a minimum error selecting step of resetting the quantization width of the parameter (i) and outputting the quantization width to the quantization unit.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, a tone input step of inputting a tone and a tone input to the tone input step are performed by QM.
A frequency band dividing step of dividing the frequency band by using an F filter, an auditory model calculating step of calculating a quantization width using an auditory model, and a time domain data processed in the frequency band dividing step as a parameter in a frequency domain. To the time-frequency conversion step, the quantization step of quantizing the frequency domain parameters from the time-frequency conversion step, based on the quantization width from the auditory model calculation unit, from the quantization step And a coding generation step of generating a coded sequence based on the various types of information described above, wherein the quantization error of the aliasing distortion of the QMF filter is calculated from the frequency domain parameters from the quantization step. The aliasing quantization error estimation step, based on the aliasing quantization error from the aliasing quantization error estimation step, the frequency Reset the quantization scale parameter of frequency, characterized in that it comprises an error width determining step of outputting the quantization width to the quantization unit.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram schematically showing a configuration of a first embodiment of the present invention. The tone encoding device of FIG. 1 is different from the conventional tone encoding device (FIG. 6) in that a minimum error selector 17 is added. Hereinafter, the operation of the added configuration will be described. Here, the frequency band dividing unit 11 (QMF filter) divides the frequency band into two for simple description, but may have a configuration other than the two.

The time-frequency conversion unit 1 performs quantization based on the precision of quantization bits in each frequency component for quantization calculated by the auditory model calculation unit 18.
From the parameters of each frequency calculated in step 2, quantized coded data such as the size of each frequency component / band parameter / quantization accuracy / quantization error / quantized data is calculated.

The minimum error selecting section 17 constitutes a feature of the present embodiment. The minimum error selecting section 17 quantizes the frequency parameter pair affecting each other based on the quantization error amount of the parameter of each frequency input from the quantization section 16. Is selected, and the information of the quantization error is output to the quantization unit 16. Based on the selected quantization error information, the quantizer 16 again calculates the magnitude of the parameter of each frequency component / band,
Quantized coded data such as quantization accuracy / quantized data is set and output to the coded sequence generation unit 19.

This embodiment will be further described with reference to FIG. The influencing frequency data pairs are frequency data located symmetrically with respect to the cutoff frequency. The operation of the minimum error selection unit 17 is as follows: as shown in FIG. 2, the frequency error width GL1 of the low frequency part closest to the center line C and the error width GH1 of the frequency near the center line C in the high frequency part. And the field GL1 has a smaller error in the low-frequency part. Therefore, GL1 is selected as the quantization error width of the two frequency components, and the quantization width of the high-frequency part is corrected from RH1 to RH1 ′. .

Similarly, the error width GL2 of the low frequency part closest to the center line C and the frequency error of the high frequency part are compared with the field GH2, and the error width GH2 of the high frequency part is small. GH2 is selected as the quantization error width of the two frequency components, and the quantization width of the low-band frequency is corrected from RL2 to RL2 '. Then, the one having the smaller quantization error width of the two frequency components is selected. Further, the quantization widths of the two frequency components are determined so that the quantization error widths of the two frequency components become the same, and output to the quantization unit 16.

As in FIG. 6, the frequency band dividing section (QMF
Filter) 11, time-frequency conversion unit 12, quantization unit 1
6. Components of the coded sequence generator 19, the auditory model calculator 18, and the minimum error estimator 17 (portion surrounded by a dotted line in FIG. 1)
Can be controlled by the encoding control unit 21. In this case, it is possible to configure the encoding control unit 21 by a computer, and realize the components in the range enclosed by the dotted line in FIG. 1 by a program, and to implement the hardware components enclosed by the dotted line in FIG. Can be realized by the respective steps shown in FIG.

Hereinafter, each step of FIG. 4 will be described. First, the processing is started in the first processing step S0, a musical sound is input in a musical sound input processing step S1, a musical sound waveform is cut out in analysis frame units, a frequency band division (band filter) processing step S2, and an auditory model. The data is output to the calculating step S4.

The frequency band division (band filter) process step S2 is to pass only the desired frequency band by passing the input musical sound waveform through a band pass (including high pass and low pass) filter. Are divided into several pieces of time waveform data, and then down-sampled to perform sampling frequency conversion.

In the time-frequency conversion step S3, time waveform data including only a specific frequency band divided into several parts is converted into frequency domain parameters for each frequency band using a method such as MDCT. I do. In the auditory model calculation step S4, the input musical sound waveform is subjected to frequency analysis using FFT or the like, and the precision of quantization bits in a frequency band for quantization is determined according to an auditory model such as simultaneous masking and minimum audibility. I do.

The quantization step S5 is based on the precision of the quantization bits in each frequency band for quantization calculated in the auditory model calculation step S4.
The accuracy of the parameters in the frequency domain calculated in the time-frequency conversion step S3 is cut off, and the size of the parameter in each frequency band, quantization accuracy, quantized encoded data such as quantized data, and the parameter of each frequency band are Calculate the quantization error. Minimum error selection step S6
Is based on the quantization error of the parameter of each frequency band calculated in the quantization step S5, selects a smaller one of a pair of quantization error of a parameter of a frequency symmetric with respect to a cutoff frequency, and performs quantization. Output to the process step S7. In the quantization step S7, the quantization accuracy of each frequency component is recalculated based on the quantization error information of the frequency component, and the magnitude of the parameter of each frequency component, the quantization accuracy, the quantization of the quantized data, and the like are again calculated. The coded data is set and output to the coded sequence generation step S8.

In the coded sequence generation step S8, quantized coded data such as the magnitude of each frequency parameter, quantization precision, and quantized data generated in the quantization step S7 are transmitted and stored, and the compression rate is calculated. Is converted to a coded sequence so as to become higher, and finally coded data is created in a coded data output step S9. In addition, these processing procedures can be realized by configuring the encoding control unit 21 of FIG. 1 by a computer and realizing it by a program, and can also be provided as a recording medium.

[Second Embodiment] FIG. 3 is a block diagram schematically showing a configuration of a second embodiment of the present invention. The tone encoding device shown in FIG. 3 is different from the conventional tone encoding device of FIG. 4 in that an aliasing distortion quantization error estimating unit 15 and an error width determining unit 17 are added. Hereinafter, operations of the added aliasing quantization error estimation unit 15 and error width determination unit 17 will be described. Hereinafter, description will be made using an example of MPEG1, Layer3. The following equation (1) is used for MPEG1, 2 Layer
3 is an equation for reducing aliasing distortion and restoring a frequency parameter to be input to the QMF filter from a frequency component in which aliasing distortion has been reduced.

[0031]

(Equation 1)

In order to remove the effect of the quantization error acoustically from this equation, Cs [i] * xr [18 * sb-1-
i] and the quantization error distortion of Ca [i] * xr [18 * sb + i] in the frequency band for quantization calculated by the auditory model calculation unit 18 of xar [18 * sb-1-i]. It can be seen that the quantization error should be smaller than the bit quantization error.

As described above, the aliasing distortion quantization error estimating unit 1
5, in the case of MPEG1, 2 Layer3,
Based on the aliasing characteristic of the QMF filter, an aliasing error is estimated from the quantization error of the frequency component.
Further, the error width determination unit 16 sets the quantization error such that the aliasing distortion quantization error is smaller than the quantization error so that the quantization error of the aliasing distortion cannot be discriminated auditory when quantizing the frequency component of the parameter. The width may be determined and output to the quantization unit 16. At this time, in FIG. 2, quantization is performed on the frequency data without reducing aliasing distortion. As described above, it is not necessary to reduce the aliasing distortion, and the aliasing distortion reducing unit for reducing the aliasing distortion may be inserted between the time-frequency conversion unit 12 and the quantization unit 16.

As in FIG. 6, the frequency band dividing unit (Q
MF filter) 11, a time-frequency converter 12, a quantizer 16, a coded sequence generator 19, an auditory model calculator 18,
Aliasing quantization error estimator 16, error width determiner 17
Can be controlled by the encoding control unit 21 (the part surrounded by a dotted line in FIG. 3). In this case, it is possible to configure the encoding control unit 21 by a computer, and realize the components in the range enclosed by the dotted line in FIG. 3 by a program, and to implement the hardware components enclosed by the dotted line in FIG. Can be realized by the respective steps shown in FIG.

Hereinafter, each step of FIG. 5 will be described. First, the processing is started in the first processing step S20, a musical sound is input in a musical sound input processing step S21, a musical sound waveform is cut out in analysis frame units, a frequency band division (band filter) processing step S22 and an auditory model calculation The data is output to the process step S24.

In the frequency band division (band filter) process step S22, the input musical tone waveform is converted into a band (high-pass,
By passing only a desired frequency band through a filter (including a low-pass), the signal is divided into several pieces of time waveform data including only a specific frequency band, and then down-sampled to perform sampling frequency conversion. The time-frequency conversion step S23 converts the time waveform data including only a specific frequency band divided into
By using such a technique as above, the parameters are converted into frequency domain parameters for each frequency band.

In the auditory model calculation step S24, the input musical sound waveform is subjected to frequency analysis using FFT or the like, and quantized bits in a frequency band for quantization are quantized in accordance with an auditory model such as simultaneous masking and minimum audibility. Determine the accuracy of The quantization step S25 includes a frequency domain parameter calculated in the time-frequency conversion step S23 based on the precision of the quantization bit in each frequency band for quantization calculated in the auditory model calculation step S24. Abort the accuracy of
The quantization error of the parameter of each frequency band and the quantized coded data such as the size of the parameter of each frequency band, quantization accuracy, and quantized data are calculated.

In the aliasing quantization error estimation step S26, the alias component of each frequency band calculated in the quantization step S25 is calculated by equation (1). Next, in the error width determination step S27, the quantization error of the aliasing distortion is set to be smaller than the quantization error so that the quantization error of the aliasing distortion cannot be discriminated auditory when quantizing the frequency component of the parameter. The quantization error width is determined and output to the quantization step S28.

In the quantization step S28, the quantization accuracy of each frequency component is recalculated based on the quantization error information of the frequency component, and the magnitude of the parameter of each frequency component, the quantization accuracy, and the quantization data are again calculated. And the like, and outputs the result to the coded sequence generation step S29. In the coded sequence generation step S29, quantized coded data such as the magnitude, quantization precision, and quantized data of each frequency generated in the quantization step S28 are transmitted and stored, and the compression ratio is increased. Into a coded sequence, and finally the coded data output step S
30 creates encoded data.

Further, these processing procedures can be realized by configuring the encoding control unit 21 of FIG. 4 with a computer and realizing it by a program, and can also be provided as a recording medium. As described above, by providing the components of the aliasing distortion quantization error estimating unit 15 and the minimum error selecting unit 17 for encoding the musical sound waveform, a code having a higher compression rate and a higher sound quality can be obtained as compared with the conventional encoding method. A decrypted tone can be generated.

[0041]

As is clear from the above, according to the present invention,
A musical tone encoding apparatus and method and musical tone code capable of achieving higher quality or a higher compression ratio because quantization is performed in consideration of the influence of the quantization error of aliasing distortion due to the frequency characteristics of the transient region of the QMF filter. A recording medium on which an encrypted program is recorded can be provided. Further, in the present invention, there is an advantage that a higher quality musical sound can be decoded by changing the encoding side without changing the conventional method at the decoding side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a musical sound encoding device of the present invention.

FIG. 2 is a diagram showing an operation example of a minimum error selection unit according to the first embodiment of the musical sound encoding device of the present invention.

FIG. 3 is a block diagram showing a configuration of a second embodiment of the musical sound encoding device of the present invention.

FIG. 4 is a flowchart showing a tone encoding process according to the tone encoding apparatus and method of the present invention.

FIG. 5 is a musical sound encoding processing procedure according to the musical sound encoding apparatus and method of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional tone encoding device.

[Explanation of symbols]

 Reference Signs List 10 Music input unit 11 Frequency band division unit 12 Time-frequency conversion unit 15 Aliasing distortion quantization error estimation unit 16 Quantization unit 17 Error width determination unit 18 Auditory model calculation unit 19 Code sequence generation unit 20 Code sequence output unit 21 Coding control unit

Claims (6)

[Claims] A tone input unit for inputting a tone; a frequency band dividing unit for dividing the tone input to the tone input unit into frequency bands using a QMF filter;
An auditory model calculating unit that calculates a quantization width using an auditory model, a time-frequency converting unit that converts time waveform data processed by the frequency band dividing unit into frequency domain parameters, and a time-frequency converting unit. A quantization unit that quantizes the frequency domain parameters from the above based on the quantization width from the auditory model calculation unit, and an encoding generation unit that generates an encoded sequence based on various information from the quantization unit In the tone encoding device, the quantization width of the parameter in the frequency domain is reset based on the information on the quantization error of the parameter in the frequency domain from the quantization unit, and the quantization width is set in the quantization unit. A tone encoding device comprising a minimum error selection unit for outputting a tone signal. 2. A tone input unit for inputting a tone, a frequency band dividing unit for dividing a tone input to the tone input unit into frequency bands by using a QMF filter,
An auditory model calculating unit that calculates a quantization width using an auditory model, a time-frequency converting unit that converts time waveform data processed by the frequency band dividing unit into frequency domain parameters, and a time-frequency converting unit. A quantization unit that quantizes the frequency domain parameters from the above based on the quantization width from the auditory model calculation unit, and an encoding generation unit that generates an encoded sequence based on various information from the quantization unit And a QMF based on the frequency domain parameter from the quantization unit.
A folding distortion quantization error estimating unit that calculates a quantization error of the aliasing of the filter; and a quantization width of a frequency domain parameter is reset based on the aliasing quantization error from the aliasing quantization error estimation unit. And a quantizing section provided with an error width determining section for outputting a quantization width. 3. A tone input step of inputting a tone, a frequency band dividing step of dividing the tone input in the tone input step into frequency bands using a QMF filter, and a quantization width using an auditory model. Calculating an auditory model to be calculated; a time-frequency conversion step of converting the time waveform data processed in the frequency band division step into a frequency domain parameter; and a frequency domain parameter from the time-frequency conversion step. A tone encoding step comprising: a quantization step of quantizing based on a quantization width from the auditory model calculation unit; and an encoding generation step of generating an encoded sequence based on various information from the quantization step. In the method, the quantization width of the parameter in the frequency domain is reset based on information on the quantization error of the parameter in the frequency domain from the quantization step. And musical sound encoding method, which comprises a minimum error selection step of outputting the quantization width to the quantization unit. 4. A tone input step of inputting a tone, a frequency band dividing step of dividing the tone input in the tone input step into frequency bands by using a QMF filter, and a quantization width by using an auditory model. An auditory model calculation step to calculate, a time-frequency conversion step of converting the time waveform data processed in the frequency band division step into frequency domain parameters, and a frequency domain parameter from the time-frequency conversion step. A musical sound encoding method comprising: a quantization step of performing quantization based on a quantization width from an auditory model calculation unit; and an encoding generation step of generating an encoded sequence based on various information from the quantization step. In the above, the QM is calculated from the frequency domain parameters obtained from the quantization step.
An aliasing distortion quantization error estimating step of calculating an aliasing distortion quantization error of the F filter; and a quantization width of a frequency domain parameter is reset based on the aliasing distortion quantization error from the aliasing distortion quantization error estimation step. And an error width determining step of outputting a quantization width to a quantization unit. 5. A tone input means for inputting a tone, a frequency band dividing means for dividing the tone input to the tone input section into frequency bands by using a QMF filter, and a quantization width by using an auditory model. Auditory model calculating means for calculating, time-frequency converting means for converting the time waveform data processed by the frequency band dividing unit into frequency domain parameters, and the frequency domain parameters from the time-frequency converting means A tone encoding device comprising: a quantization unit that performs quantization based on a quantization width from an auditory model calculation unit; and a coding sequence calculation unit that calculates a coding sequence based on various types of information from the quantization unit. A recording medium for recording a program for performing frequency domain parameter quantization information from the quantization means based on the information on the quantization error of the frequency domain parameter from the quantization means. Calculates the quantization width of the parameters, the calculated recording medium recording audio coding program for quantization parameters in the quantization means based on the quantization width. 6. A tone input unit for inputting a tone, a frequency band dividing unit for dividing a tone input to the tone input unit into frequency bands using a QMF filter, and a quantization width using an auditory model. Auditory model calculating means for calculating the time-domain data processed by the frequency band dividing means into a frequency-domain parameter; and a frequency-domain parameter from the time-frequency converting means. A tone encoding device comprising: a quantization unit that performs quantization based on a quantization width from an auditory model calculation unit; and an encoding generation unit that generates an encoded sequence based on various types of information from the quantization unit. Recording medium for recording a program for performing a QM from a parameter in the frequency domain from the quantization means.
An aliasing distortion quantization error estimating means for calculating a quantization error of aliasing distortion of the F filter; and a quantization width of a frequency domain parameter is calculated based on the aliasing distortion quantization error from the aliasing distortion quantization error estimating means. And a recording medium for recording a program for tone encoding in which a parameter is quantized by quantization means based on the calculated quantization width.