JP2002368622A - Encoder and encoding method, decoder and decoding method, recording medium, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder that encodes data, without increasing the scale of an encode sequence table as in the case of employing multi-dimensional variable length codes. SOLUTION: A control section 31 controls an encoding section 32 for encode the quantized spectra 401 comprising a group of M-sets of spectra signals after negative quantized spectra, for example, are converted into positive values (by absolute value processing), to unify the positive and negative of the quantized spectra. Further, the control section 31 controls an encoding section 33, to encode data corresponding to positions of a particular value (value 0) and the negative quantized spectra in the group, by using number of bits on the basis of number of the quantized spectra other than those with the particular value among M-sets of the quantized spectra and to generate information for identifying the negative quantized spectra.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding apparatus and method, a decoding apparatus and method, a recording medium, and a program, and performs encoding, transmission, recording, and reproduction of input digital data by so-called high-efficiency encoding. The present invention relates to an encoding device and method, a decoding device and method, a recording medium, and a program suitable for use in obtaining a reproduced signal by decoding.

[0002]

2. Description of the Related Art There are various methods for high-efficiency encoding of signals such as audio or voice. For example, an audio signal or the like on a time axis is divided into a plurality of frequency bands and encoded without being blocked. Sub-band coding (sub-band coding: SBC (Subband Coding)), which is a non-blocking frequency band division method, or converting a signal on the time axis to a signal on the frequency axis (spectral conversion), A divided frequency band division method in which the frequency band is divided into frequency bands and encoded for each band, so-called conversion encoding, or the like can be used.

[0003] Also, a high-efficiency coding method combining the above-mentioned band division coding and transform coding has been considered.
In this case, for example, after band division is performed by band division coding, the spectrum of the signal in each band is converted into a signal on the frequency axis, and the spectrum-converted band is encoded. Here, as a filter for band division described above, for example, a QMF filter (Quadrature Mirror Filter)
For example, 1976 RECrochier
e Digital coding of speech in subbands, Bell Sys
t.Tech. J. Vol.55, No.8, 1976.

Also, ICASSP 83, BOSTON Polyphase Quadr
ature filters-A new subband coding technique, Jose
ph H. Rothweiler describes an equal bandwidth filter partitioning technique. Here, as the above-mentioned spectral transform, for example, an input audio signal is divided into blocks in a predetermined unit time (frame), and a discrete Fourier transform (DFT), a discrete cosine transform (Discrete Cosine Transform) is performed for each block. (DCT), Modified Discrete Cosine Transfo
rm) (MDCT) or the like, there is a spectrum conversion that converts the time axis to the frequency axis. For MDCT, for example, ICASSP 1987 Subband / Transform Coding Using Filt
er Bank Designs Based on Time Domain Aliasing Canc
ellation, JPPrincen ABBradley Univ. of Surr
ey Royal Melbourne Inst. of Tech.

[0005] By quantizing the signal divided for each band by the filter or the spectrum conversion as described above,
A band in which quantization noise is generated can be controlled, and a more efficient coding can be perceptually performed by utilizing properties such as a masking effect. Further, if the normalization is performed for each band, for example, with the maximum value of the absolute value of the signal component in the band before performing the quantization, more efficient coding can be performed.

[0006] As a frequency division width for quantizing each frequency component divided into frequency bands, for example, band division is performed in consideration of human auditory characteristics. That is, an audio signal may be divided into a plurality of bands (for example, 32 bands) in a band generally called a critical band (critical band) such that the higher the band, the wider the bandwidth. When encoding data for each band at this time, predetermined bits are allocated to each band, or encoding is performed by adaptive bit allocation (bit allocation) for each band. .

For example, when the coefficient data obtained by the MDCT processing is encoded by the bit allocation, adaptively to the MDCT coefficient data for each band obtained by the MDCT processing for each block. The encoding is performed with a small number of allocated bits. The following two methods are known as bit allocation methods.

The first method is Adaptive Transform Codin
g of Speech Signals, R. Zelinskiand P. Noll, IEEE Tr
ansactions of Accoustics, Speech, and Signal Process
ing, vol. ASSP-25, No. 4, August 1977. Here, bit allocation is performed based on the magnitude of the signal for each band. In this method, the quantization noise spectrum becomes flat and the noise energy is minimized.
The sense of noise is not optimal because the masking effect is not used for the sense of hearing.

The second method is ICASSP 1980 The crit
ical band coder-digital encodingof the perceptual
requirements of the auditory system, MAKransner
Disclosed to MIT. Here, a method is described in which a necessary signal-to-noise ratio is obtained for each band by using auditory masking and fixed bit allocation is performed. However, in this method, even when the characteristic is measured with a sine wave input, the characteristic value is not so good because the bit allocation is fixed.

[0010] In order to solve these problems, all bits that can be used for bit allocation include a fixed bit allocation pattern predetermined for each small block and a bit allocation depending on the signal size of each block. A high-efficiency coding apparatus has been proposed in which a division ratio is used depending on the amount to be performed, and the division ratio depends on a signal related to an input signal, and the smoother the spectrum of the signal, the larger the division ratio into the fixed bit allocation pattern. ing.

According to this apparatus, when energy is concentrated on a specific spectrum such as a sine wave input, a large number of bits are allocated to a block including the spectrum, thereby significantly improving the entire signal-to-noise characteristic. Can be improved. In general, human hearing is extremely sensitive to signals having steep spectral components. Therefore, using such a method to improve the signal-to-noise characteristics merely improves the numerical values measured. In addition, it is effective in improving sound quality in terms of hearing.

[0012] Many other methods of bit allocation have been proposed. In addition, if an auditory model is refined and the capacity of the encoding device is increased, a code that is more efficient in terms of auditory sense will be provided. Becomes possible.

The present inventors have also disclosed in Japanese Patent Application No. 5-15286.
No. 5 has previously proposed a method of separating a tone component, which is particularly important in terms of audibility, from a spectral signal and coding the component separately from other spectral components. As a result, it is possible to efficiently encode an audio signal or the like at a high compression rate with almost no audible deterioration.

When the above-described DFT or DCT is used as a method of converting a waveform signal into a spectrum, M independent real number data can be obtained by performing conversion using a time block including M samples. In order to reduce the connection distortion between time blocks, each block usually overlaps the neighboring blocks with M1 samples each, so on average, DF
In T or DCT, M real number data is quantized and encoded for (M-M1) samples.

On the other hand, when the above-mentioned MDCT is used as a method of converting into a spectrum, independent 2N samples are overlapped with N times each of the adjacent times.
Since M pieces of real number data are obtained, on average, the MDCT quantizes and codes M pieces of real number data for M samples. In the decoding device, it is possible to reconstruct the waveform signal from the code obtained by using the MDCT in this way by adding the waveform elements obtained by performing the inverse transform in each block while interfering with each other. it can.

In general, by extending the time block for the transformation, the frequency resolution of the spectrum is increased,
Energy concentrates on specific spectral components. Therefore, the DFT is performed by using a MDCT in which the conversion is performed with a long block length by overlapping the neighboring blocks by half each and the number of obtained spectral signals does not increase with respect to the number of original time samples. It is possible to perform more efficient coding than when DCT or DCT is used.
In addition, by providing a sufficiently long overlap between adjacent blocks, distortion between blocks of a waveform signal can be reduced.

In constructing an actual code sequence, first, quantization accuracy information and normalization coefficient information are encoded with a predetermined number of bits for each band in which normalization and quantization are performed. What is necessary is just to encode the quantized spectrum signal.

For encoding a spectrum signal, a method using a variable length code such as a Huffman code is known. For Huffman codes, for example,
DavidA. Huffman, "A Method for the Construction of
Minimum-Redundancy Codes ", Proceedings of the I.
RE, pp 1098-1101, Sep., 1952.

Further, a plurality of spectral signals are collected into one
A method using a multidimensional variable length code expressed by two codes is known. Generally, in an encoding method using a multidimensional variable length code, as the order of the code is larger, more efficient encoding can be performed in terms of compression efficiency. However, as the order increases, the size of the code string table dramatically increases, which causes a problem in practical use. In practice, an optimal order according to the purpose is selected in consideration of the compression efficiency and the size of the code string table.

In general, in an acoustic waveform signal, energy is often concentrated on a fundamental frequency component and a frequency component that is an integral multiple of the fundamental frequency, that is, a so-called harmonic component, and the level of a spectrum signal around the frequency is higher than that of a so-called harmonic component. Since it is very small, the probability of being quantized to zero increases. In order to efficiently encode such a signal, it is sufficient to encode a spectrum signal quantized to 0 having a large occurrence probability with a minimum amount of information.
When a one-dimensional variable length code is used, even if each spectrum signal is encoded with the shortest code length of 1 bit, N
The spectrum of the book requires N bits of information. Order N
In the case of using the multi-dimensional variable-length code, since N spectra can be encoded with the shortest code length of 1 bit, efficient encoding can be performed on a signal having frequency components as described above. Can be performed.

However, in the encoding method using a multidimensional variable length code, increasing the order of the code has a considerable advantage in terms of compression efficiency, but in consideration of practical use, the code of the code is not limited. It is impossible to increase the order.

Normally, a code string table is prepared for each piece of quantization accuracy information set for each band. If the quantization precision is low, the value of the spectral signal that can be represented is small, so increasing the order does not increase the size of the code string table so much, but if the quantization precision is high, the value of the spectral signal that can be represented Therefore, even if the order is increased by one, the size of the code string table is significantly increased.

The above will be further described with reference to specific examples. Now, it is assumed that an input signal is subjected to MDCT conversion and a spectrum as shown in FIG. 1 is obtained. FIG. 1 shows the absolute value of the spectrum of the MDCT with the level converted to dB. The input signal is converted into 64 spectral signals for each predetermined time block, and these are combined into eight coding units [1] to [8], and normalization and quantization are performed.

By changing the quantization accuracy for each coding unit depending on the distribution of the frequency components, it is possible to minimize the deterioration of the sound quality and perform audio-efficient coding. The quantization accuracy information required in each coding unit can be obtained, for example, by calculating a minimum audible level and a masking level in a band corresponding to each coding unit based on an auditory model. The normalized and quantized spectrum signal is converted into a variable length code, and is encoded in each encoding unit together with quantization accuracy information and normalization information.

FIG. 2 is a diagram for explaining a method of expressing quantization accuracy information. When the quantization accuracy information code is expressed by 3 bits, up to eight types of quantization accuracy information can be set. In this example, 1, 3, 5, 7, 15, 31, 63, or 1
The quantization is performed by any of the eight steps of 27 steps. Here, being quantized in one step means that the spectral signals in the coding unit are all quantized to a value of zero.

FIG. 3 is a diagram for explaining a conventional variable-length coding method. The spectrum signal is quantized based on quantization accuracy information determined for each coding unit, and a quantized spectrum is obtained. When encoding the quantized spectrum, it is converted into a corresponding code string by referring to a code string table as shown in FIG.
As is clear from FIG. 4, a code string table is prepared for each piece of quantization accuracy information.

In FIG. 3, in the coding unit [1], a code “011” is selected as quantization accuracy information. Therefore, as shown in FIG. 4, quantization is performed in seven steps, and the values of the quantized spectrum signals (quantized spectrum) are in order from the lowest frequency.
3, -1, 2, and 2. When these are converted into code strings using the code string table in which the quantization accuracy information code of FIG. 4 is “011”, they are 1110, 101, 1100, and 110, respectively.
0, and the code lengths are 4, 3, 4, and 4, respectively.

In the coding unit [2], a code "010" is selected as quantization accuracy information. In this case, as shown in FIG. 4, quantization is performed in five steps. In this example, the quantization spectrum is -2, 1, 0, 1 in order from the lowest frequency. These are converted into code strings using the code string table with the quantization accuracy information code of “010” in FIG.
0, 0, 100, and the code lengths are 3, 3, 1,
It becomes 3.

Similarly, in the coding unit [3], the code “001” is selected as the quantization accuracy information.
The quantization is performed by the number of steps in the step, the quantized spectrum is 0, -1, 0, 0, the code sequence is 0, 11, 0, 0, and the code length is 1, 2, 1, 1.

FIG. 5 is a diagram for explaining a two-dimensional variable length coding method. FIG. 5 shows the same encoding unit as in FIG.

Assuming that a two-dimensional code string table as shown in FIG. 6 is used as the code string table when the quantization accuracy information code is “001”, the coding unit [3] in FIG.
Are grouped into one group by two and converted into one code string. Therefore, the quantized spectra of the four spectral signals 0, -1, 0,
0s are grouped into two groups of (0, -1) and (0, 0) and are converted into two code strings of 101 and 0.

When the spectrum signal of the coding unit [3] is coded with a one-dimensional variable length code as shown in FIG. 3, the required information amount is 1 + 2 + 1 + 1 = 5 bits. On the other hand, as shown in FIG. 5, when encoding is performed using a two-dimensional variable length code, the information amount is 3 + 1 = 4 bits. That is, it can be seen that when the degree is increased, encoding can be performed with a smaller amount of information.

[0033]

As described above,
Quantized spectra of a plurality of (N) spectral signals are grouped into one group to form N-dimensional data,
By encoding this into a variable length code according to the code string table, the code length can be reduced as compared with the case where a one-dimensional variable length code is used. However, when the order (the value of N) increases, the size of the code string table significantly increases, and there is a problem that practical use becomes difficult.

For example, when a two-dimensional variable length code is used, the quantization accuracy information code is "001", "01".
As shown in FIGS. 6 to 8, the code sequence table in the case of 0 ″ and “110” has a larger code sequence table than the code sequence table in the case of using a one-dimensional variable length code (FIG. 4). I have.

The present invention has been made in view of such a situation, and performs encoding with a short code length without increasing the size of a code string table as in the case of using multidimensional variable length encoding. Is what you can do.

[0036]

An encoding apparatus according to the present invention comprises:
The unifying means for adjusting the sign of the numerical values to unify the positive and negative of the M numerical values, the first encoding means for encoding the numerical value whose sign is unified by the unifying means, and the positive and negative signs adjusted by the unifying means Second encoding means for generating and encoding positive / negative information for specifying a numerical value, and code string generation for generating a code string including an output of the first encoding means and an output of the second encoding means Means.

The code string generating means can generate the code string so as to include the output of the first coding means and the output of the second coding means alternately.

The second encoding means includes a calculating means for calculating the number of numerical values other than the specific value among the M numerical values, and a calculating means for determining whether the sign of the numerical value other than the specific value has been adjusted. And generating means for generating the number obtained by the above and making the information positive and negative.

The encoding means can encode the numerical value into a variable-length code string.

The variable-length code string can be a Huffman code.

The numerical sequence can be a quantized acoustic waveform signal.

The encoding method of the present invention adjusts the sign of the numerical values to unify the positive and negative of the M numerical values, and encodes the numerical values of which the sign is unified by the processing of the unifying step. An encoding step, a second encoding step of generating and encoding positive / negative information for specifying a numerical value whose sign has been adjusted in the processing of the unifying step, and an output in the processing of the first encoding step. A code string generating step of generating a code string including an output in the processing of the second encoding step.

The program of the first recording medium of the present invention comprises:
A unifying step of adjusting the sign of the numerical values to unify the sign of the M numbers, a first encoding step of encoding a numerical value of which the sign is unified by the unifying step processing, and a positive or negative sign by the processing of the unifying step A second encoding step for generating and encoding the positive / negative information for specifying the numerical value adjusted by, an output in the processing of the first encoding step, and an output in the processing of the second encoding step And a code string generating step of generating a code string including the following.

A first program according to the present invention is a unifying step for adjusting the sign of a numerical value to unify the sign of M numbers, and a first step for encoding a numerical value of which the sign is unified by the processing of the unifying step. , A second encoding step of generating and encoding positive / negative information for specifying a numerical value whose sign has been adjusted in the processing of the unifying step, and an output in the processing of the first encoding step And causing the computer to execute processing including a code string generation step of generating a code string including an output in the processing of the second encoding step.

In the encoding apparatus and method of the present invention, the program of the first recording medium, and the first program, the sign of the M values is adjusted so that the sign of the M numbers is unified, and the sign is unified. The calculated numerical value is encoded, and positive / negative information for specifying the numerical value with the adjusted positive / negative is generated and encoded to generate a code string.

The decoding apparatus of the present invention adjusts the sign of the first code string, which is encoded as one group by unifying the signs of the numbers forming the M number strings, and the sign is adjusted when the signs are unified. Input means for receiving a code string including a second code string obtained by encoding information for specifying the calculated numerical value; decoding means for decoding the first code string; decoding means for decoding the second code string; To read information for identifying the adjusted numerical value
Based on the read means, the M number-positive / negative value sequence decoded by the decoding means, and the information for specifying the positive / negative value read by the first reading means. And a restoring means for restoring the sign of the numerical sequence.

The input means can receive a code string containing the first code string and the second code string alternately.

The first reading means includes calculating means for calculating the number of numerical values other than the specific value out of the M numerical values, and information for determining whether the sign of the numerical value other than the specific value has been adjusted by the calculating means. Second reading means for reading the obtained number can be provided.

The second reading means can not read the second code string when the specific value is decoded by the decoding means.

The specific value can be the value 0.

According to the decoding method of the present invention, the positive and negative values are adjusted when unifying the positive and negative values of the numerical value constituting the M numerical value sequences into a first code sequence encoded as one group. An input step of receiving a code string including a second code string obtained by encoding information for specifying the calculated numerical value, a decoding step of decoding the first code string, and a decoding step of decoding the second code string. A first reading step of reading information for specifying the adjusted numerical value, a sequence of M numbers of positive / negative numbers adjusted in the decoding step, and a number sequence read in the first reading step. A restoring step of restoring the sign of the M number sequence based on the information for specifying the numerical value whose sign has been adjusted.

The program of the second recording medium of the present invention comprises:
The first code string, which is encoded as one group by unifying the signs of the numbers constituting the M number strings, and the information for specifying the numbers whose signs have been adjusted when unifying the signs, are encoded. An input step of receiving a code string including the converted second code string, and a decoding step of decoding the first code string;
A first reading step of decoding the second code string and reading information for specifying the numerical value of which the sign has been adjusted, and a number string of M signs adjusted in the decoding step, A restoring step of restoring the sign of the M number sequence based on the information for specifying the sign whose sign has been adjusted read in the processing of the first reading step.

The second program according to the present invention provides a first code string which is encoded as one group by unifying the sign of the numerical values constituting the M number string and the sign when the sign is unified. An input step of receiving a code string including a second code string in which information for specifying the adjusted numerical value is encoded; a decoding step of decoding the first code string; and a decoding step of decoding the second code string. , A first reading step of reading information for specifying a numerical value whose positive / negative has been adjusted, a sequence of M positive / negative numerical values decoded in the processing of the decoding step, and a processing of the first reading step. Based on the read information for identifying the adjusted numerical value, M
And restoring the sign of the number sequence.

In the decoding device and method according to the present invention, the program of the second recording medium, and the second program, the positive and negative values constituting the M number sequence are unified and encoded as one group. A code string including a first code string and a second code string that encodes information for specifying a numerical value whose sign has been adjusted when unifying the positive and negative signs is received, and the first code string is decoded. And a second code string is decoded, information for identifying the positive / negative adjusted numerical value is read, and the decoded M positive / negative adjusted numerical string;
Based on the read information for specifying the adjusted numeric value, the positive / negative of the M number sequence is restored.

[0055]

FIG. 9 shows an example of the configuration of an encoding apparatus to which the present invention is applied.

The signal waveform 10 input to this encoding device
1 is converted into a signal frequency component 102 by a conversion circuit 1, each component is encoded by a signal component encoding circuit 2, and a code sequence is generated by a code sequence generation circuit 3. This code string is transmitted to a predetermined transmission path or recorded on the information recording medium 4.

FIG. 10 shows a configuration example of the conversion circuit 1.

The signal components 211 and 212 divided into two bands by the band division filter 11 are converted into spectral signal components 221 and 222 by forward spectrum conversion circuits 12 and 13 such as MDCT in each band. It has been done. The bandwidth of the signals 211 and 212 is １ ／ of the bandwidth of the signal 201 (signal 2
01 has been decimated to 1/2).

Note that 201 in FIG. 10 is replaced with 101 in FIG.
221 and 222 in FIG. 10 respectively correspond to 102 in FIG.

A large number of conversion circuits 1 can be considered in addition to this embodiment. For example, the input signal may be directly converted to a spectrum signal by MDCT, or DF instead of MDCT.
It may be converted by T or DCT.

Although it is possible to process a signal without converting it into a spectrum simply by dividing a signal into band components by a band division filter, the method of the present invention is particularly effective when energy is concentrated at a specific frequency. Therefore, it is convenient to adopt a method of converting a large number of frequency components into frequency components by spectral conversion that can be obtained with a relatively small amount of calculation.

FIG. 11 shows a configuration example of the signal component encoding circuit 2.

Each signal component 301 is normalized by the normalizing circuit 21 for each predetermined band, and is then input as a signal 302 to the quantizing circuit 22 where the quantization precision determining circuit 2
3 is quantized on the basis of the quantization precision signal 303 calculated in Step 3 and is output as a signal 304. 11 corresponds to 102 in FIG. 9, and 304 in FIG. 11 corresponds to 103 in FIG. 9, respectively.
Here, 304 (103) includes normalization coefficient information and quantization accuracy information in addition to the quantized signal components.

FIG. 12 shows a configuration example of the code sequence generation circuit 3.

The control unit 31 controls the quantization spectrum 401 of the spectrum signals grouped into M groups by one.
For example, after converting a negative quantized spectrum into a positive value (obtaining an absolute value) and unifying the positive and negative of the quantized spectrum, the encoding unit 32 controls the encoding unit 32 to encode it.

Further, the control unit 31 controls the encoding unit 33 to calculate the number of bits based on the number of quantized spectra other than the specific value (in this example, the value 0) among the M quantized spectra. Information for coding a specific value and a position within a group of negative quantized spectra within a group, and specifying a negative quantized spectrum (hereinafter, positive / negative sign information
sign).

The code sequence (code sequence of the quantized spectrum) 402 generated by the coding unit 32 and the coding unit 33
403 (sign information sign) 403 generated by
Is output to a predetermined transmission path or the information recording medium 4.

Note that reference numeral 401 in FIG.
In addition, 402 and 403 in FIG. 12 correspond to 104 in FIG. 9, respectively.

Next, the operation of the encoding device (FIG. 9) will be described. The acoustic waveform signal 101 (201) is input to the band division filter 11 (FIG. 10) of the conversion circuit 1, and a lower frequency signal component 211 and a higher frequency signal component 2
12 are divided. Lower frequency signal component 211
Is input to the forward spectrum conversion circuit 12 and converted into a spectrum signal component 221. Similarly, the higher frequency signal component 212 is input to the forward spectrum conversion circuit 13, converted into a spectrum signal component 222, and output.

That is, with reference to FIG. 1, the forward spectrum transform circuit 12 unitizes a lower frequency spectrum signal to generate coding units [1] to [6]. Further, the forward spectrum conversion circuit 13
Unitizes the higher frequency spectral signal components to generate coding units [7], [8].

The spectrum signal components 221 and 222 (102) output from the forward spectrum conversion circuits 12 and 13
Is the normalization circuit 21 of the signal component encoding circuit 2 (FIG. 11)
Is input to the quantization accuracy determination circuit 23. Normalization circuit 2
1 divides the value of each signal by its maximum value among a plurality of spectral signal components in the encoding unit,
Perform normalization. Then, the obtained normalization coefficient 302 is supplied to the quantization circuit 22.

The quantization accuracy determination circuit 23 determines the quantization accuracy of the input spectral signal component by encoding unit by calculating the minimum audible level and masking level in the band corresponding to each encoding unit. I do. The quantization circuit 22 quantizes the normalization coefficient 302 supplied from the normalization circuit 21 with the quantization precision 303 supplied from the quantization precision determination circuit 23, and obtains the obtained quantization spectrum 3
04 (103) is supplied to the code string generation circuit 3.

The code string generation circuit 3 calculates the quantization spectrum 3
04 is converted into a code string.
This will be described with reference to the flowchart of FIG.

In step S1, the code string generation circuit 3
The control unit 31 initializes the value of the counter i, which counts the number of spectral signals grouped into one group, and the value of the register N and the value of the register sign to a value of 0.

Next, in step S2, the control unit 31
Is a spectrum signal corresponding to the value of the counter i (hereinafter, referred to as
The quantization spectrum of QSP (i) is examined as appropriate, and it is determined whether or not it is a specific value (value 0 in this example). If it is not 0, step S3 is performed.
Proceed to.

In step S3, the control section 31 increases the value of the register N by 1 and shifts the value of the register sign by 1 bit to the left (doubles).

Next, in step S4, the control unit 31
Determines whether the quantized spectrum of QSP (i) is a negative value. If it is determined that the quantized spectrum is a negative value, the process proceeds to step S5.

In step S5, the control unit 31
The quantization spectrum of SP (i) is multiplied by the value −1, and the resulting value is used as the quantization spectrum of QSP (i). That is, when the quantization spectrum of QSP (i) is a negative value, it is converted to a positive value. At this time, the control unit 31 increases the value of the register sign by one.

If it is determined in step S4 that the quantized spectrum of QSP (i) has a positive value, the process proceeds to step S4.
5 is skipped, the process proceeds to step S6, and in step S2, the quantized spectrum of QSP (i) is set to the value 0.
If it is determined that step S3 to step S3
Step 5 is skipped, and the process proceeds to step S6.

In step S6, the control section 31 increases the value of the counter i by 1, and in step S7, determines whether or not the value of the counter i is less than the number M of the spectral signals grouped into one group. Judge
If it is determined that it is less than M, the process returns to step S2, and the subsequent processing is executed.

If it is determined in step S7 that the value of the counter i is not less than the number M of spectrum signals (if it is more than M), the process proceeds to step S8, where the control unit 31
Controls the encoding unit 32 to control QSP (0) through QSP
The quantized spectrum of (M-1), that is, the quantized spectrums grouped into one group, is encoded with an M-dimensional variable length code.

For example, when a two-dimensional variable length code is performed (when M = 2), the encoding unit 32 collects the data into one group by referring to a code string table as shown in FIG. The two quantized spectra are converted into a corresponding code sequence.

FIG. 14 shows that the quantization accuracy information code is “0”.
01 ”, a code string table of“ 010 ”,
And the code string table for “011” are shown,
These code string tables include a code string of 4 words, a code string of 9 words,
A code string of 16 words is prepared.

In the case of this example, since the negative value quantized spectrum is converted into a positive value (step S5), the negative value quantized spectrum is not encoded. Therefore, the code string table of FIG. 14 does not include a code string corresponding to a negative-valued quantized spectrum. Thus, for example, by unifying the quantization spectrum to a positive value,
Since there is no need to prepare a code string corresponding to the negative quantization spectrum, the scale of the code string table can be reduced accordingly.

On the other hand, in the conventional variable-length code, a code string corresponding to a quantized spectrum of a positive value and a negative value must be prepared, so that the scale of the code string becomes large. For example, in the code string table in the case where the quantization accuracy information code in the two-dimensional variable length code is “001”,
The code string of 9 words shown in FIG. 6 is prepared, the code string table of “010” is prepared with the code string of 25 words shown in FIG. 7, and the code string table of “011” is , It is necessary to prepare the code string of 49 words shown in FIG.

Although not shown, in the case of four dimensions, the quantization accuracy information codes are "010" and "01".
At 1 ″, the size of the code string table of the present invention is 81 words and 256 words, but in the conventional case, it is 625 words and 24 words.
It becomes 01 words.

Returning to FIG. 13, in step S9, the control unit 31 controls the encoding unit 33 to encode the value of the register sign with the same number of bits as the value of the register N, and sign information sign ( (Code sequence).

After that, the process ends, and the processes of steps S1 to S9 are similarly performed on the quantized spectrums of the spectrum signals grouped into the next group.

Next, as shown in FIG. 15, a coding unit having 16 spectral signals (in the example of FIG. 1, [7]
Alternatively, the operation of the above-described code sequence generation circuit 3 will be described again by taking the coding unit of [8] as an example. In this case, the spectrum signal of the coding unit is 2 (=
M) Books are grouped into one group.

When encoding the quantized spectrum (1, -2) of the two spectral signals from the lower frequency, when the counter i = 0, the register N = 0, and the register sign = 0 (step S1), QSP
Since the quantized spectrum (value 1) of (0) is not the value 0 (step S2), the value 0 of the register N is increased by 1 to a value 1, and the value 0 of the register sign is doubled to a value 0. (Step S3).

Since the quantized spectrum (value 1) of QSP (0) is a positive value (step S4), the value 0 of the counter i is increased by 1 to 1 (step S4).
6).

The quantization spectrum of QSP (1) (value−
Since 2) is not the value 0, the value 1 of the register N is further increased by 1 to a value 2, and the value 0 of the register sign is doubled to a value 0.

Since the quantization spectrum (value-2) of QSP (1) is a negative value, 2 (= -2 × -1) is
The quantized spectrum of the QSP (1) to be encoded is set (step S5). At this time, the value of the register sign is 0.
Increases by 1 to a value of 1.

That is, in this case, (1, 2) is encoded as one unit into 5-bit "11110" based on the code string table of FIG. 14 (step S8), and subsequently, the value 1 of the register sign is set. Is encoded into the number of bits of the value 2 of the register N, that is, a 2-bit code string “01” to generate positive / negative sign information sign “01” (step S9).

The sign information sign indicates that the value corresponding to the "1" and encoded in step S8 is a negative value. In this case, (1, -2) is encoded as (1, 2), but the sign information "sign"
01 ”indicates that“ 2 ”of (1, 2) corresponding to“ 1 ”is originally a negative value (−2). The sign of the signal component is determined based on the sign.

In the present invention, the encoding unit shown in FIG. 15 is a 5-bit "11110" ((1, 2)
Code string) and 2-bit “01” (register of value 1)
sign code string), 1-bit “0” ((0, 0) code string), 3-bit “101” ((1, 0) code string) and 1-bit “0” (value 0 Register sign code string, 3-bit "110" (code string of (1,1)) and 2-bit "10" (code sign of register sign of value 2), 1-bit "0" ((0 , 0) code string), 5 bits of “11100” ((0, 2) code string) and 1
Bit “0” (code string of register sign of value 0), 3-bit “110” (code string of (1, 1)) and 2-bit “11” (code string of register sign of value 3), And a 5-bit "11100" (a code string of (0, 2)) and a 1-bit "0" (a code string of a register sign of value 0), the code length of which is 35 (= 7 + 1 + 4)
+ 5 + 1 + 6 + 5 + 6). The conventional two-dimensional variable length code has 35 bits as shown in FIG.

FIG. 17 shows an example of the configuration of a decoding device for decoding and outputting an audio signal from a code sequence generated by the coding device of FIG.

The information recording medium 4 has been transmitted or
The code of each signal component is extracted by the code sequence decomposition circuit 41 from the code sequence 501 reproduced from
2 by the signal component decoding circuit 42
3 is decoded, and an acoustic waveform signal 504 is generated and output by the inverse conversion circuit 43.

FIG. 18 shows an example of the configuration of the code string decomposition circuit 41.

The control section 51 controls the decoding section 52 to read the code sequence of the quantized spectrum (to be exact, all positive codes) read from the code sequence 601 of the coding unit input to the code sequence decomposition circuit 41. The code sequence of the quantized spectrum having the value is decoded.

The controller 51 also reads the sign information sign from the code string 601 of the encoding unit, detects the sign of the quantized spectrum based on the sign information sign, and determines the sign of the signal component. .

The reference numeral 601 in FIG. 18 corresponds to the reference numeral 501 in FIG.
Reference numeral 602 in FIG. 8 corresponds to reference numeral 502 in FIG.

FIG. 19 shows a configuration example of the inverse conversion circuit 43. This corresponds to the conversion circuit 1 shown in FIG.
The signals 711 and 712 of each band obtained from the band 02 are synthesized by the band synthesizing filter 63 and output as a signal 721. 701 and 70 in FIG.
2 corresponds to 503 in FIG. 17, and 721 in FIG.
4 respectively.

Next, the operation of the decoding device will be described.
The code string decomposition circuit 41 performs a code string decomposition process as shown in the flowchart of FIG.

In step S21, the control unit 51
By controlling the decoding unit 52, the QSP (0) read from the code string of the coding unit and combined into one group
To QSP (M−1) to decode the code string of the quantized spectrum (code string of the quantized spectrum converted to a positive value). Note that M is the number of spectral signals that are grouped into one group when encoded.

In step S22, the control unit 51
It is determined whether or not all the values obtained by the decoding in step S21 are 0, and if not, the process proceeds to step S23.

In step S23, sign information sign (sign information sign indicating the sign of the quantized spectrum) input following the code string of the quantized spectrum is read. Details of the processing here are shown in the flowchart of FIG.

In step S31, the control unit 51
The values of the built-in counter i and the register N are
Initially set to the value 0.

Next, in step S32, the control unit 5
1 determines whether or not the value corresponding to QSP (i) and obtained by decoding in step S21 is a value 0;
If it is determined that the above condition is satisfied, the process proceeds to step S34.

On the other hand, if it is determined in step S32 that the value is not 0, the process proceeds to step S33, where the control unit 51
Increments the value of the register N by 1 and proceeds to step S34.
Proceed to.

At step S34, the control unit 51
The value of the counter i is increased by 1, and in step S35, it is determined whether or not the value of the counter i is less than the number M of the spectrum signals to be grouped into one group.
If it is determined that the difference is less than the predetermined value, the process returns to step S32, and the subsequent processing is executed.

If it is determined in step S35 that the value of the counter i is not less than the number M of spectrum signals (if it is more than M), the process proceeds to step S36, where the control unit 5
1 reads the code string of the number of bits of the value of the register N from the next bit of the code string read in step S21 of the code string of the encoding unit as the sign information sign.

Thereafter, the process proceeds to step S24 in FIG.
The signs of QSP (0) to QSP (M-1) are determined. Details of the processing here are shown in the flowchart of FIG.

In step S41, the control unit 51
The value of the counter i is initialized to 0, and the value 1 set in the register mask is shifted to the left by the number of bits corresponding to the value obtained by subtracting 1 from the value of the register N at this time. Let it.

At step S42, the control unit 51
It is determined whether the value obtained by decoding in step S21 corresponding to QSP (i) is a value 0, and if it is determined that the value is not 0, the process proceeds to step S43 and is read in step S36. Sign information and register mask
Is calculated, and it is determined whether or not the calculation result is a value 0.

If it is determined in step S43 that the result of the AND operation is not the value 0, the value obtained by decoding in step S21 corresponding to QSP (i) is subtracted by the value -1.
, And the process proceeds to step S45.

On the other hand, if it is determined in step S43 that the calculation result of the logical product is 0, the process in step S44 is skipped, and the flow advances to step S45.

In step S45, the control unit 51
Shift the value of the register mask right by one bit,
Proceed to step S46.

If it is determined in step S42 that the value corresponding to QSP (i) obtained by decoding in step S21 is 0, steps S43 to S43
The process of step 45 is skipped, and the process proceeds to step S46.

In step S46, the control unit 61
The value of the counter i is increased by 1, and in step S47, it is determined whether the value of the counter i is less than the number M of the spectral signals combined into one group, and it is determined that the value is less than M. In this case, the process returns to step S42, and the subsequent processing is executed.

If it is determined in step S47 that the value of the counter i is not less than M (if it is more than M),
Along with the processing here (the processing of step S24), FIG.
When the processing of step S1 is completed, the processing of step S1 and subsequent steps is similarly performed on the code string of the next input quantized spectrum.

Next, as an example of decoding the encoded coding unit shown in FIG.
Will be described again.

The code string “11110” read first
Is decoded (step S21), and (1, 2) is obtained. Since (1,2) is not (0,0) (step S22), the sign information “01” that is input following the code string “11110” is read (step S23).

Specifically, of (1, 2), the QSP
Since the value 1 corresponding to (0) is not the value 0 (step S32), the value 0 of the register N increases by 1 to become 1 (step S33), and the value 0 of the counter i increases by 1. The value becomes 1 (step S34).

Since the value 2 corresponding to QSP (1) is not 0 in (1, 2), the value 1 of the register N is further increased by 1 to the value 2, and the value of the counter i is increased. 1 is increased by 1 to a value of 2.

In this case, the value 2 of the register N is calculated from the next bit of the code string “11110” of the quantized spectrum.
, Ie, two bits of data “01”
Is read as the sign information sign.

Next, the signs of QSP (0) and QSP (1) are determined (step S24).

Specifically, the value of the counter i is initialized to 0, and 1 set in the register mask is shifted leftward by 1 (= value of register N−value 1) bits. . That is, the register mask becomes (10) (step S41).

Since the value 1 corresponding to QSP (0) is not 0 in (1, 2) (step S42), the logical product of the sign information (sign (01)) and the register mask (10) is calculated. Since the calculation result is 0 (step S43), the register mask (10) is shifted rightward by one bit to become (01) (step S45).
That is, since the value 1 corresponding to QSP (0) was originally a positive value, the value 1 is directly used as the sign of QSP (0).

The value 0 of the counter i increases by 1 to become 1 (step S46).

Of (1, 2), the value 2 corresponding to QSP (1) is not 0, so that sign (01)
And the logical product of the register mask (01) at this time is calculated, and the calculation result is the value 1, so that the value 2 corresponding to QSP (1) is multiplied by the value -1 to obtain the value -2. (Step S44).

That is, the value 2 corresponding to QSP (1)
Is originally a negative value, and is thus set to the value -2 as described herein, which is used as the sign of QSP (1).

The code 502 (FIG. 17) extracted by the code string decomposing circuit 41 is input to the signal component decoding circuit 42 and decoded. This signal component decoding circuit 42 performs a process reverse to that of the signal component encoding circuit 2 shown in FIG.

In the signal 503 output from the signal component decoding circuit 42, the lower frequency spectrum signal component 701 is input to the inverse spectrum converter 61, and the higher frequency spectrum signal component 702 is inverted. The signal is input to the spectrum conversion circuit 62. The inverse spectrum conversion circuits 61 and 62 convert the input spectrum signal components 701 and 702 into acoustic signals 711 and 711 on the time axis, respectively.
712, and outputs the result to the band synthesis filter 63. The band synthesis filter 63 outputs the lower frequency sound signal 71.
1 and an audio signal 712 of a higher frequency are synthesized and output as a synthesized audio signal 721 (504).

In general, an acoustic waveform signal often has energy concentrated in a fundamental frequency and a frequency component that is an integral multiple of the fundamental frequency, that is, a so-called harmonic component, and the spectral signal of other frequency components is zero even if quantized. There are many. The higher the fundamental frequency, the greater the distance between the so-called harmonic components, and therefore the higher the probability of occurrence of a quantized spectrum of 0. In addition, a signal having such a frequency component, unless quantization is performed with a higher quantization precision, a sufficient amount of information is consumed because a sufficient signal-to-noise ratio in audibility cannot be secured. In particular, the amount of information consumed is large in a band in which the width of the coding unit is wide.

Therefore, in order to efficiently encode such a signal, it is important to encode the spectrum signal quantized to 0 with a small amount of information.
The best known method is to use a multi-dimensional variable-length code, but as described above, a huge amount of code string table is required, which is not practical. However, the method according to the present invention achieves efficient encoding without increasing the size of the code sequence table.

As described above, a signal obtained by subjecting a signal once subjected to a band division filter to spectrum conversion by MDCT is used as a band division circuit, and an inverse MDCT (IMD
Although the embodiment using the inverse spectrum transformed by (CT) and applied to the band synthesizing filter has been described, it is needless to say that the MDCT transform and the IMDCT transform are performed directly without using the band dividing filter and the band synthesizing filter. You may do it. Also, the type of spectrum conversion is not limited to MDCT, and DFT, DCT, etc. may be used.

Further, the band division and the band synthesis may be performed only by the band division filter and the band synthesis filter without using the spectrum conversion. In this case, a band divided by the filter or a band obtained by combining a plurality of these bands is defined as an encoding unit. However, the method of the present invention can be applied efficiently by performing spectral conversion such as MDCT and converting into a large number of spectral signals, and then configuring the coding unit as described using the embodiment. .

In the above description, the case of processing an acoustic waveform signal has been described. However, the method of the present invention can be applied to other types of signals, for example, to image signals. It is possible. However, the present invention realizes efficient encoding when there are many spectral signals quantized to 0 by using the characteristics of the acoustic waveform signal, and therefore, when the acoustic waveform signal is used for the acoustic waveform signal. Demonstrate power.

Further, the method according to the present invention can be used in combination with a conventional method using a variable length code. For example, when the quantization precision is low, that is, when the number of quantization steps is small, encoding is performed using a two-dimensional or four-dimensional code sequence table by a conventional method, and the quantization precision is high, that is, the number of quantization steps is large. In the case where is large, it is more effective if the encoding is performed using the method according to the present invention in consideration of the scale of the code string table.

Further, the above-described series of processing can be realized by hardware, but can also be realized by software. When a series of processing is realized by software, a program constituting the software is installed in a computer, and the program is executed by the computer, so that the above-described encoding device and decoding device are functionally realized. Is done.

FIG. 23 is a block diagram showing the configuration of an embodiment of the computer 101 functioning as the above-described encoding device or decoding device. CPU (Central Pro
), an input / output interface 116 is connected to the CPU 111 via a bus 115.
When a user inputs a command through the input / output interface 116 from an input unit 118 including a keyboard, a mouse, and the like, for example, the ROM (Read Only Memory) 11
2. A program stored in a recording medium such as a magnetic disk 131, an optical disk 132, a magneto-optical disk 133, or a semiconductor memory 134 mounted on the hard disk 114 or the drive 120 is stored in a RAM (Random).
Access Memory) 113 for execution. Thus, the various processes described above (for example, the processes shown by the flowcharts in FIGS. 13 and 20) are performed. Further, the CPU 111 transmits the processing result to an LCD (Liquid Crystal Diode) via the input / output interface 116, for example.
splay) or the like is output as necessary. The program is stored on the hard disk 114 or RO
M112 is stored in advance and provided to the user integrally with the computer 101, the magnetic disk 131, the optical disk 132, the magneto-optical disk 133, the semiconductor memory 1
34, packaged media such as satellite,
It can be provided to the hard disk 114 via a communication unit 119 from a network or the like.

In this specification, the step of describing a program provided by a recording medium may be performed not only in chronological order but also in chronological order according to the described order. This also includes processing executed in parallel or individually.

[0144]

According to the encoding apparatus and method of the present invention, the program of the first recording medium, and the first program, the sign of the numerical values is adjusted to unify the sign of the M numerical values, and Encodes a unified numerical value, generates and encodes positive / negative information for identifying a numerical value whose positive / negative has been adjusted,
Since a code string including them is generated, for example, encoding with high compression efficiency can be performed without increasing the size of the code string table.

According to the decoding device and method of the present invention, the program of the second recording medium, and the second program,
The first code string, which is encoded as one group by unifying the signs of the numbers constituting the M number strings, and the information for specifying the numbers whose signs have been adjusted when unifying the signs, are encoded. Receiving a code string including the converted second code string, decoding the first code string, decoding the second code string, reading information for specifying a numerical value whose sign has been adjusted, and decoding the information. Based on the M number-adjusted numeric value sequence and the read information for identifying the adjusted numeric value,
Since the sign of the M number sequences is restored, for example, encoding with high compression efficiency can be performed without increasing the size of the code sequence table.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a spectrum of an encoding unit.

FIG. 2 is a diagram illustrating a method of expressing quantization accuracy information.

FIG. 3 is a diagram illustrating an encoding method using a variable length code according to the related art.

FIG. 4 is a diagram illustrating an example of a code string table.

FIG. 5 is a diagram illustrating an encoding method using a multidimensional variable length code according to the related art.

FIG. 6 is a diagram showing an example of a multidimensional code string table according to the related art.

FIG. 7 is a diagram showing an example of another multi-dimensional code string table according to the related art.

FIG. 8 is a diagram showing an example of another multidimensional code string table according to the related art.

FIG. 9 is a block diagram illustrating a configuration example of an encoding device to which the present invention has been applied.

FIG. 10 is a block diagram illustrating a configuration example of a conversion circuit in FIG. 9;

11 is a block diagram illustrating a configuration example of a signal component encoding circuit in FIG. 9;

12 is a block diagram illustrating a configuration example of a code string generation circuit in FIG. 9;

FIG. 13 is a flowchart illustrating an operation of the code sequence generation circuit.

FIG. 14 is a diagram illustrating an example of a code string table used in the present invention.

FIG. 15 is a diagram illustrating an encoding method according to the present invention.

FIG. 16 is another diagram illustrating an encoding method according to the related art.

FIG. 17 is a block diagram illustrating a configuration example of a decoding device to which the present invention has been applied.

18 is a block diagram illustrating a configuration example of a code string decomposition circuit in FIG. 17;

19 is a block diagram illustrating a configuration example of the conversion circuit of FIG.

FIG. 20 is a flowchart illustrating the operation of the code string decomposition circuit.

FIG. 21 is a flowchart illustrating a process in step S23 of FIG. 20;

FIG. 22 is a flowchart illustrating a process in step S24 of FIG. 20;

FIG. 23 is a block diagram illustrating a configuration example of a computer 101.

[Explanation of symbols]

Reference Signs List 1 conversion circuit, 2 signal component coding circuit, 3 code string generation circuit, 4 information recording medium, 11 band division filter, 12 forward spectrum conversion circuit, 13 forward spectrum conversion circuit, 21 normalization circuit, 22 quantization circuit, 23 Quantization accuracy determination circuit, 31 control unit,
32 encoding unit, 33 encoding unit, 41 code string decomposition circuit, 42 signal component decoding circuit, 43 inverse conversion circuit, 51 control unit, 52 decoding unit, 53 decoding unit, 61, 62 inverse spectrum conversion circuit, 63
Band synthesis filter

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Minoru Tsuji F-term (reference) in Sony Corporation 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo 5D045 DA00 5J064 AA02 AA04 BA09 BA16 BC01 BC02 BD03

Claims (17)

[Claims] 1. An encoding apparatus that encodes numerical values forming a sequence of numerical values collectively into one group each of M numbers, wherein the sign of the numerical values is adjusted to unify the sign of the M numerical values. Means, first encoding means for encoding the numerical value of which the sign is unified by the unifying means, and sign information for identifying the numerical value whose sign is adjusted by the unifying means is generated and encoded. An encoding apparatus comprising: a second encoding unit; and a code sequence generation unit configured to generate a code sequence including an output of the first encoding unit and an output of the second encoding unit. 2. The apparatus according to claim 1, wherein said code string generation means generates a code string so as to include an output of said first encoding means and an output of said second encoding means alternately. An encoding device according to claim 1. 3. The second encoding means includes: a calculation means for calculating the number of the numerical values other than the specific value among the M numerical values; and whether the sign of the numerical value other than the specific value has been adjusted. 2. The encoding apparatus according to claim 1, further comprising: generating means for generating the number of pieces of information by the number obtained by the calculating means to generate positive / negative information. 4. The encoding device according to claim 1, wherein the encoding unit encodes the numerical value into a variable-length code string. 5. The encoding apparatus according to claim 4, wherein the variable-length code string is formed of a Huffman code. 6. The encoding apparatus according to claim 1, wherein the numerical sequence is a quantized acoustic waveform signal. 7. An encoding method for an encoding apparatus, which encodes numerical values constituting a numerical value sequence into a group of M numbers at a time, adjusting the sign of the numerical values, and adjusting the sign of the M numerical values. A first encoding step of encoding the numerical value of which the sign is unified in the processing of the unifying step; A second encoding step for generating and encoding information; a code sequence for generating a code sequence including an output in the process of the first encoding step and an output in the process of the second encoding step And a generating step. 8. A program for an encoding apparatus for encoding numerical values constituting a numerical sequence into a group of M numbers each, wherein the program adjusts the sign of the numerical values and adjusts the sign of the M numerical values. A first encoding step of encoding the numerical values of which the sign is unified in the processing of the unifying step; and a positive / negative sign for specifying a numerical value whose sign has been adjusted in the processing of the unifying step. A second encoding step for generating and encoding information; a code sequence for generating a code sequence including an output in the process of the first encoding step and an output in the process of the second encoding step A recording medium on which a computer-readable program is recorded. 9. A program for an encoding apparatus for encoding numerical values constituting a numerical sequence into a group of M numbers each, wherein the program adjusts the sign of the numerical values and adjusts the sign of the M numerical values. A first encoding step of encoding the numerical value of which the sign is unified in the processing of the unifying step; and a positive / negative value for specifying a numerical value of which the sign is adjusted in the processing of the unifying step. A second encoding step for generating and encoding information; a code sequence for generating a code sequence including an output in the process of the first encoding step and an output in the process of the second encoding step A program for causing a computer to execute a process including a generation step. 10. A first code string, which is encoded as one group by unifying the signs of the numbers forming the M number strings, and a number whose sign has been adjusted when unifying the signs. Input means for receiving a code string including a second code string obtained by encoding information for performing decoding, decoding means for decoding the first code string, decoding the second code string, and adjusting the sign. First reading means for reading the information for specifying the read numerical value; M number-positive / negative value sequences decoded by the decoding means; and positive / negative values read by the first reading means are adjusted. Decoding means for restoring the sign of the M number sequence based on the information for specifying the obtained numerical value. 11. The decoding apparatus according to claim 10, wherein said input means receives a code string containing said first code string and said second code string alternately. 12. The first reading means comprises: calculating means for calculating the number of the numerical values other than the specific value of the M numerical values; and determining whether the sign of the numerical value other than the specific value has been adjusted. 11. The decoding device according to claim 10, further comprising: a second reading unit that reads information by the number obtained by the calculation unit. 13. The apparatus according to claim 12, wherein the second reading unit does not read the second code string when the specific value is decoded by the decoding unit.
3. The decoding device according to claim 1. 14. The decoding device according to claim 12, wherein the specific value is a value 0. 15. A first code string which is encoded as one group by unifying the positive and negative values of numerical values constituting M numerical value strings, and a numerical value whose positive and negative are adjusted when the positive and negative are unified. An input step of receiving a code string including a second code string obtained by encoding information for performing decoding, a decoding step of decoding the first code string, and a decoding step of decoding the second code string so that the sign is adjusted. A first reading step of reading the information for specifying the decoded numerical value; a M number of positive / negative adjusted numerical strings decoded in the processing of the decoding step; and a numerical string read in the processing of the first reading step. A restoring step of restoring the sign of the M number sequence based on the information for specifying the sign whose sign has been adjusted. 16. A first code string, which is encoded as one group by unifying the signs of the numbers forming M number strings, and a number whose sign is adjusted when the signs are unified. An input step of receiving a code string including a second code string obtained by encoding information for performing decoding, a decoding step of decoding the first code string, and a decoding step of decoding the second code string so that the sign is adjusted. A first reading step of reading the information for specifying the decoded numerical value; a M number of positive / negative adjusted numerical strings decoded in the processing of the decoding step; and a numerical string read in the processing of the first reading step. A restoring step of restoring the sign of the M number sequence based on the information for specifying the sign whose sign has been adjusted. . 17. A first code string which is encoded as one group by unifying the positive and negative values of numerical values constituting M numerical value strings, and a numerical value whose positive and negative have been adjusted when the positive and negative are unified. An input step of receiving a code string including a second code string obtained by encoding information for performing decoding, a decoding step of decoding the first code string, and a decoding step of decoding the second code string so that the sign is adjusted. A first reading step of reading the information for specifying the decoded numerical value; a M number of positive / negative adjusted numerical strings decoded in the processing of the decoding step; and a numerical string read in the processing of the first reading step. And a restoring step of restoring the sign of the M number sequence based on the information for specifying the numerical value whose sign has been adjusted.