JPH09135173A - Device and method for encoding, device and method for decoding, device and method for transmission and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve encoding efficiency as a whole. SOLUTION: When quantization precision information expressing a quantization step used in quantization and difference quantization precision information being difference from a prescribed reference value are 0, +1 and -1, pieces of quantization precision information are respectively encoded to 0, 100 and 101. In the meantime, unless difference quantization precision information is 0, +1 and -1, quantization precision information is encoded in a form having a prescribed unique pattern (escape code) added with the quantization precision information itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding device and an encoding method, a decoding device and a decoding method, a transmission device and a transmission method, and a recording medium. In particular, for example, digital data such as an audio signal is highly efficiently coded, recorded on a transmission or recording medium, and on the decoding side,
The present invention relates to an encoding device and an encoding method that receives or reproduces and decodes this, a decoding device and a decoding method, a transmission device and a transmission method, and a recording medium.

[0002]

2. Description of the Related Art Conventionally, as a method for highly efficient encoding an audio signal such as voice, for example, a non-blocking frequency band division method represented by band division encoding (subband coding (SBC)), A blocking frequency band division method typified by transform coding is known.

In the non-blocking frequency band division method, an audio signal on the time axis is divided into a plurality of frequency bands and encoded without being divided into blocks. In addition, in the block frequency band division method, a signal on the time axis is converted into a signal on the frequency axis (spectrum conversion) and divided into a plurality of frequency bands (coefficients obtained by spectrum conversion are calculated for each predetermined frequency band). In summary), each band is encoded.

As a method for further improving the coding efficiency, a combination of the non-blocking frequency band division method (band division coding) and the blocking frequency band division method (transform coding) has been proposed. According to this method, for example, after band division is performed by band division encoding, the signal for each band is spectrum-converted into a signal on the frequency axis, and encoding is performed for each spectrum-converted band. Done.

Here, when frequency band division is performed, for example, a QMF (Quadrature Mirror Filter) is often used because the processing is simple and aliasing distortion is eliminated. For details of frequency band division by QMF, see, for example, “1976 RE Crochiere, Digital coding.
of speech in subbands, Bell Syst. Tech. J. Vol.5
5, No. 8 1976 ”and the like.

Further, as a method for performing band division, there are other methods such as an equal bandwidth filter division method. For details, see "ICASSP 83, BOSTON P
olyphase Quadrature filters-A new subband coding t
echnique, Joseph H. Rothweiler ”.

On the other hand, as the above-mentioned spectrum conversion,
For example, the input audio signal is divided into blocks in a predetermined unit time (frame), and a discrete Fourier transform (DFT), a discrete cosine transform (DCT), a modified DCT transform (MDCT), etc. are performed for each block so that the time axis becomes a frequency axis. There is something to convert.

Regarding the MDCT, for example, "IC
ASSP 1987, Subband / Transform Coding Using Filter B
ank Designs Based on Time Domain Aliasing Cancella
tion, JPPrincen, ABBradley, Univ. of Surrey R
The details are described in "oyal Melbourne Inst. of Tech."

When a signal for each band obtained by a filter or spectrum conversion is quantized, the band in which the quantization noise is generated can be controlled, and by using the characteristics such as the masking effect, it is auditory higher. Efficient encoding can be performed. Further, if the signal component for each band is normalized by the maximum absolute value of the signal component in that band before the quantization, for example, more efficient encoding can be performed. .

The width of each frequency band when performing band division is
For example, it is determined in consideration of human auditory characteristics. That is, generally, for example, the audio signal is divided into a plurality of bands (for example, 25 bands) with a band width that increases in a higher band called a critical band.

Further, when the data for each band is encoded, a predetermined bit allocation is made for each band or an adaptive bit allocation (bit allocation) is made for each band. That is, for example, when encoding coefficient data obtained by MDCT processing by bit allocation, the number of bits is adaptively adjusted with respect to MDCT coefficient data of each band obtained by MDCT processing a signal for each block. Are assigned and encoded.

As a bit allocation method, for example, a method of bit allocation based on the signal size of each band (hereinafter, appropriately referred to as a first bit allocation method) or aural masking is used. There is known a method of obtaining a required signal-to-noise ratio for each band and performing fixed bit allocation (hereinafter, appropriately referred to as a second bit allocation method).

Regarding the first bit allocation method, for example, "Adaptive Transform Coding of Speech Signals,
R. Zelinski and P. Noll, IEEE Transactions of Accous
tics, Speech, and Signal Processing, vol.ASSP-25, No.
4, August 1977 ”and the like for details.
For the second bit allocation method, for example, “ICASSP
1980, The critical band coder digital encoding of
the perceptual requirements of the auditory syst
For details, see "em, MAKransner MIT".

According to the first bit allocation method, the quantization noise spectrum becomes flat and the noise energy becomes minimum. However, since the masking effect is not used auditorily, the actual noise feeling is not optimal. Further, in the second bit allocation method, even when energy is concentrated at a certain frequency, for example, when a sine wave is input, the bit allocation is fixed, so that the characteristic value is not so good.

Therefore, all bits that can be used for bit allocation are divided into 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 which uses the signal and makes its division ratio dependent on the signal related to the input signal, that is, the smoother the spectrum of the signal is, the larger the division ratio to the fixed bit allocation pattern is. .

According to this method, when energy is concentrated on a specific spectrum, such as a sine wave input, many bits are allocated to a block including the spectrum, so that the overall signal-to-noise characteristic is increased. Can be dramatically improved. In general, human hearing is extremely sensitive to a signal having a steep spectral component, so improving the signal-to-noise characteristic as described above does not only improve the numerical value of measurement, It is effective for improving the sound quality in terms of hearing.

Many other methods have been proposed as the bit allocation method. If the model relating to hearing is further refined and the performance of the coding apparatus is improved,
From an auditory point of view, more efficient coding becomes possible.

Further, the applicant of the present invention filed Japanese Patent Application No. 5-1528.
No. 65 previously filed a method for separating a tone-like component, which is particularly important for hearing, from a spectrum signal and encoding the component separately from other spectrum components. According to this method, it is possible to efficiently encode an audio signal or the like at a high compression rate with almost no auditory deterioration.

When DFT or DCT is used as a method of converting a waveform signal into a spectrum, M independent real number data is obtained by performing conversion with a time block consisting of M samples. However, in order to reduce the connection distortion between time blocks (frames), it is usually 1
One block consists of blocks on both sides and a predetermined number M
Since it is configured by overlapping one sample at a time, in the coding method using DFT or DCT, M average real number data is quantized and coded for (M-M1) samples. Will be changed.

When MDCT is used as a method for converting a signal on the time axis into a spectrum, independent M real number data are obtained from 2M samples that overlap N blocks of both adjacent blocks. Is obtained. Therefore, in this case, on average, M pieces of real number data are quantized and coded for M pieces of samples.
In this case, in the decoding device, M
A waveform signal is reconstructed by adding waveform elements obtained by performing inverse transformation in each block from a code obtained using DCT while interfering with each other.

Generally, by lengthening the time block (frame) for conversion, the frequency resolution of the spectrum is increased and the energy is concentrated on a specific spectral component. Therefore, when using the MDCT in which the number of spectral signals obtained does not increase with respect to the number of original time samples, the DFT and D
It is possible to perform more efficient encoding than when using CT. 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 string, first, for each band in which normalization and quantization are performed, quantization precision information (information indicating a quantization step when performing quantization) and a normalization coefficient. (Value used for normalizing each signal component) may be encoded with a predetermined number of bits, and then the normalized and quantized spectrum signal may be encoded.

Here, for example, ISO / IEC 1117
2-3: 1993 (E), a993 describes a high-efficiency coding method in which the number of bits representing the quantization accuracy information is set to be different depending on the band.
It is standardized that the higher the band, the smaller the number of bits representing the quantization accuracy information.

FIG. 12 shows an example of the configuration of a conventional encoding device that encodes an audio signal by dividing it into frequency bands. The audio signal to be encoded is input to the band dividing unit 1 and band-divided into, for example, signals of four frequency bands.

Here, in the band division unit 1, the above-mentioned QM
It is also possible to perform band division using a filter such as F, or to perform band division by performing spectrum conversion such as MDCT and grouping the resulting spectrum signals into bands. You can also do it. Furthermore, the filter bank divides the audio signal into several frequency bands, spectrum-converts the signals in each band, and outputs the resulting spectrum signal as
It is also possible to perform band division by grouping for each band.

The width of each band (hereinafter also referred to as an encoding unit) when band-dividing the audio signal by the band dividing unit 1 is uniform, for example, and is adjusted to the critical bandwidth. It may be uneven. FIG.
In the embodiment, the audio signal is divided into four coding units, but the number of coding units is not limited to this.

The signal decomposed into four coding units (hereinafter, each of the four coding units will be referred to as first to fourth coding units as appropriate) is quantized for each predetermined time block (frame). It is supplied to the conversion accuracy determination unit 3. Further, the signals of the first to fourth encoding units are
It is also supplied to the normalization units 2 _{1 to} 2 ₄ .

The normalizing sections 2 _{1 to} 2 ₄ extract the one having the maximum absolute value from the respective signal components constituting the respective signals of the input first to fourth encoding units, and extract the extracted one.
To normalization coefficients of the fourth coding unit. Then, in the normalization sections 2 _{1 to} 2 ₄ , the respective signal components forming the signals of the first to fourth coding units are respectively normalized by the normalization coefficients of the first to fourth coding units. (Divided). Therefore, in this case, the normalized data obtained by normalization has a value in the range of -1.0 to 1.0.

The normalized data is output from the normalizing units 2 _{1 to} 2 ₄ to the quantizing units 4 _{1 to} 4 ₄ , respectively. Further, the normalization coefficients of the first to fourth coding units are output to the multiplexer 6 from the normalization units 2 _{1 to} 2 _4, respectively.

The quantizing units 4 _{1 to} 4 ₄ are supplied with the normalized data of the first to fourth encoding units from the normalizing units 2 _{1 to} 2 ₄ respectively, and the quantizing precision determining unit 3 From this, the quantization accuracy information for instructing the quantization step when quantizing the normalized data of the first to fourth encoding units is also supplied.

That is, the quantization precision determination unit 3 outputs each of the normalized data of the first to fourth encoding units based on the signals of the first to fourth encoding units from the band division unit 1. Determine the quantization step when quantizing. Then, the quantization accuracy information of the first to fourth coding units corresponding to the quantization step is transferred to the quantization units 4 _{1 to} 4 ₄
To the multiplexer 6 as well.

In the quantizers 4 _{1 to} 4 ₄ , the normalized data of the first to fourth encoding units are subjected to quantization steps corresponding to the quantization accuracy information of the first to fourth encoding units. Each of them is quantized and coded, and the resulting quantized coefficients of the first to fourth coding units are output to the multiplexer 6. Multiplexer 6
Then, the quantized coefficient, the quantized accuracy information, and the normalized coefficient of the first to fourth encoding units are encoded as necessary and then multiplexed. Then, the encoded data obtained as a result is transmitted via a transmission line or is recorded on a recording medium.

In the quantization precision determining unit 3, the determination of the quantization step is performed based on the signal obtained by band division, for example, based on the normalized data, the masking effect, etc. The auditory phenomenon can be taken into consideration.

Next, FIG. 13 shows an example of the configuration of a decoding device for decoding the encoded data output from the encoding device of FIG. The encoded data is input to the demultiplexer 21, decoded, and separated into the quantized coefficients of the first to fourth encoding units, the quantization accuracy information, and the normalized coefficient. The quantization coefficient, the quantization accuracy information, and the normalization coefficient of the _{first to fourth} coding units are supplied to the signal component forming units 23 _{1 to} 23 ₄ corresponding to the respective coding units.

In the signal component construction unit 23 ₁ , the quantized coefficient of the first coding unit is dequantized in the quantization step corresponding to the quantization accuracy information of the first coding unit,
Thereby, the normalized data of the first encoding unit is obtained. Further, in the signal component construction unit 23 ₁ , the normalized data of the first coding unit is multiplied by the normalization coefficient of the first coding unit, whereby the signal of the first coding unit is decoded. It is output to the band synthesis unit 24.

The same processing is performed in the signal component constructing sections 23 _{2 to} 23 ₄ , whereby the signals of the second to fourth coding units are decoded and output to the band synthesizing section 24. In the band synthesizing unit 24, the signals of the first to fourth coding units are band-synthesized, and thereby the original audio signal is restored.

Since the encoded data supplied (transmitted) from the encoding device of FIG. 12 to the decoding device of FIG. 13 includes the quantization accuracy information, the auditory model used in the decoding device is arbitrary. Can be set to. That is, in the coding device, the quantization step for each coding unit can be set freely, and with the improvement of the computing power of the coding device and the refinement of the auditory model, without changing the decoding device, It is possible to improve the sound quality and the compression rate.

However, in this case, the number of bits for encoding the quantization accuracy information itself becomes large, and it is difficult to improve the overall encoding efficiency above a certain value.

Therefore, instead of directly encoding the quantization accuracy information, there is a method of determining the quantization accuracy information from the normalization coefficient in the decoding device. In this method, when the standard is determined, there is a method. Since the relationship between the normalization coefficient and the quantization precision information is determined, it will be difficult to introduce the quantization precision control based on a more advanced auditory model in the future. Further, when the compression rate to be realized has a range, it becomes necessary to determine the relationship between the normalization coefficient and the quantization accuracy information for each compression rate.

Therefore, in order to further improve the compression rate from a certain value, not only the coding efficiency of the object of direct coding (main information) (audio signal in the case of FIG. 12) is increased but also quantization is performed. Such as accuracy information and normalization factors,
It is necessary to improve the coding efficiency of sub information that is not the target of direct coding.

Therefore, the applicant of the present application has filed Japanese Patent Application Laid-Open No. 6-216
As disclosed in Japanese Laid-Open Patent Publication No. 782, efficient coding of a difference between a reference quantization precision information pattern (hereinafter, appropriately referred to as reference quantization precision information) and the quantization precision information to be encoded. Has previously proposed a method of performing efficient compression while maintaining the degree of freedom in giving the quantization step.

However, in this method, since the difference between the quantization accuracy information to be encoded and the reference quantization accuracy information is always encoded, it is possible to obtain the quantization accuracy information itself to be encoded. If the number of bits is small, the coding efficiency will deteriorate.

Therefore, the applicant of the present invention filed Japanese Patent Application Laid-Open No. 7-193.
As disclosed in Japanese Patent Laid-Open No. 510-510, a difference between directly encoded sub information such as quantization accuracy information and a normalization coefficient and previously encoded sub information (hereinafter, appropriately referred to as difference sub information) We have previously proposed a method of comparing the number of bits with that of encoded data, and encoding the sub information with the smaller number of bits.

[0044]

However, in this method, the sub information itself is coded or the difference from the differential sub information is coded for each block (frame) or for each group in which several coding units are collected. Is determined, and the encoding is performed with a fixed number of bits, so that sub information of a specific encoding unit (specific frequency band) is included in one block or group. It has been difficult to deal with the case where the encoding efficiency is improved by encoding as it is and by encoding the difference sub-information for the other sub-information.

Therefore, whether the sub information itself is encoded, or
Alternatively, there is a method of improving the coding efficiency of the sub information by setting the coding unit as a unit for designating whether to code the differential sub information. However, when encoding is performed by selecting whether to encode the sub information itself or the differential sub information, which method is used to make the decoding side recognize the selected method. It is necessary to include a flag indicating whether or not the encoded data is included. Therefore, if it is possible to specify whether to encode the sub information itself or the difference sub information in a fine unit such as an encoding unit, the number of required flags increases, and the result There is a problem that it is difficult to perform efficient coding.

That is, for example, one block is composed of 16 coding units and the sub information itself is coded,
Alternatively, in order to be able to specify whether to encode the differential sub-information in block units, as shown in FIGS. 14A and 14B, one flag (here Then, when the 1-bit control flag) is assigned and the differential sub-information is encoded, that flag is set to
For example, it is set to 1 (FIG. 14A), and when the sub information itself is encoded, the flag may be set to 0 (FIG. 14B).

In this case, when the differential side information in all 16 coding units can be coded within the predetermined bit length A, the flag is set to 1 (FIG. 14).
(A)) As a result, the sub information is encoded into a predetermined short bit length A. On the other hand, if any one of the 16 pieces of difference sub-information cannot be encoded within the predetermined bit length A, the flag is set to 0 (FIG. 14 (b)). Therefore, as shown by hatching in FIG. 14B, when even one piece of the differential side information of one of the 16 encoding units cannot be encoded within the predetermined bit length A, 16 For all coding units,
The sub information itself is encoded into a bit length B longer than a predetermined bit length A.

On the other hand, in FIG. 14C, one group is composed of four coding units, and whether the sub information itself is coded or the differential sub information is coded is designated for each group. It is designed to be able to.
In this case, as shown by hatching in FIG.
When the differential side information of a certain one of the six encoding units cannot be encoded within the predetermined bit length A, the side information itself is only for the group including that encoding unit. Is encoded. Therefore, as compared with the case in FIG. 14B, efficient encoding can be performed. However, in this case, the flag is 4
You need one.

However, even in this case, when the differential side information that cannot be encoded within the predetermined bit length A is dispersed in the block, the side information has a long bit length in most encoding units. It will be encoded into B.

Therefore, as shown in FIG. 14D, if a control flag is prepared for each encoding unit, it is possible to select, for each encoding unit, either the sub information itself or the differential sub information to be encoded. This makes it possible to efficiently code the sub information.

However, in this case, the same number of control flags as the number of coding units are required, and the overall coding efficiency is deteriorated.

The present invention has been made in view of such a situation, and makes it possible to further improve the coding efficiency.

[0053]

According to a first aspect of the present invention, there is provided an encoding apparatus according to one of the first and second methods, depending on whether or not encoding target information to be encoded satisfies a predetermined condition. An encoding unit that selects one of the methods and encodes the information to be encoded by the selected method is provided, and the information to be encoded is encoded by either one of the first and second methods. It is characterized in that the data obtained by the conversion includes a predetermined unique pattern.

According to a thirteenth aspect of the present invention, one of the first and second methods is selected depending on whether or not the information to be encoded, which is the object of encoding, satisfies a predetermined condition. A data obtained by encoding the information to be encoded by one of the first and second methods, which is an encoding method for encoding the information to be encoded by the selected method. Is configured to include a predetermined unique pattern.

A decoding device according to a fourteenth aspect of the present invention determines whether or not the encoded data is configured to include a predetermined unique pattern, and based on the result of the determination, determines whether the encoded data is the first or the first encoded data. It is characterized in that it comprises a decoding means for decoding by either one of the two methods.

A decoding method according to a fifteenth aspect of the present invention determines whether or not the encoded data is configured to include a predetermined unique pattern, and based on the result of the determination, the encoded data is first or first encoded. It is characterized in that the decoding is performed by either one of the two methods.

According to a sixteenth aspect of the present invention, the transmission apparatus selects one of the first and second methods depending on whether the encoding target information to be encoded satisfies a predetermined condition, A transmission device, comprising: a coding means for coding the coding target information by the selected method, for transmitting the coded data output from the coding means, wherein the coding target information is the first or second coding data. The data obtained by encoding by any one of the above methods is configured to include a predetermined unique pattern.

According to a seventeenth aspect of the present invention, in the transmission method, one of the first and second methods is selected depending on whether or not the encoding target information to be encoded satisfies a predetermined condition. A transmission method for encoding the encoding target information by the selected method and transmitting the encoded data obtained as a result, wherein the encoding target information is set to one of the first and second methods. It is characterized in that the data obtained by encoding by the method includes a predetermined unique pattern.

The recording medium according to claim 18 selects one of the first and second methods depending on whether or not the encoding target information to be encoded satisfies a predetermined condition, A recording medium on which encoding target information is encoded by the selected method, and encoded data obtained as a result is recorded, and the encoding target information is stored in one of the first and second methods. The data obtained by encoding by the method of 1) is configured to include a predetermined unique pattern.

In the encoding device according to the first aspect,
The encoding means selects either the first method or the second method depending on whether or not the encoding target information to be encoded satisfies a predetermined condition, and the encoding is performed by the selected method. The target information is encoded.
In this case, the encoding target information is set to the first or second
The data obtained by encoding by any one of the above methods is configured to include a predetermined unique pattern.

In the encoding method of the thirteenth aspect, one of the first and second methods is selected depending on whether or not the encoding object information to be encoded satisfies a predetermined condition. Then, the information to be encoded is encoded by the selected method. In this case, the data obtained by encoding the encoding target information by any one of the first and second methods is configured to include a predetermined unique pattern.

In the decoding device according to the fourteenth aspect, the decoding means determines whether or not the encoded data is configured to include a predetermined unique pattern, and based on the determination result, the encoding is performed. The data is decoded by one of the first and second methods.

In the decoding method according to the fifteenth aspect, it is judged whether or not the coded data is configured to include a predetermined unique pattern, and the coded data is first or Decoding is performed by either one of the second methods.

In the transmission apparatus according to claim 16,
The encoding means selects one of the first and second methods depending on whether or not the encoding target information that is the object of encoding satisfies a predetermined condition, and performs encoding using the selected method. The target information is encoded.
In this case, the encoding target information is set to the first or second
The data obtained by encoding by any one of the above methods is configured to include a predetermined unique pattern.

In the transmission method according to claim 17,
Depending on whether or not the encoding target information to be encoded satisfies a predetermined condition, one of the first and second methods is selected, and the encoding target information is encoded by the selected method. , And the resulting encoded data is transmitted. In this case, the data obtained by encoding the encoding target information by any one of the first and second methods is configured to include a predetermined unique pattern.

In the recording medium according to the eighteenth aspect, one of the first and second methods is selected depending on whether or not the encoding target information to be encoded satisfies a predetermined condition. The information to be encoded is encoded by the selected method, and the encoded data obtained as a result is recorded. In this case, the data obtained by encoding the encoding target information by any one of the first and second methods is configured to include a predetermined unique pattern.

[0067]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but before that, in order to clarify the correspondence between each means of the invention described in the claims and the following embodiments. The features of the present invention are described as follows by adding a corresponding embodiment (however, an example) in parentheses after each means.

That is, the encoding apparatus according to the first aspect uses either the first method or the second method depending on whether the encoding target information to be encoded satisfies a predetermined condition. An encoding unit (for example, the quantization accuracy information encoding unit 5 shown in FIG. 1) that selects and encodes the encoding target information by the selected method is provided, and the encoding target information is
It is characterized in that data obtained by encoding by either one of the first and second methods is configured to include a predetermined unique pattern.

A decoding device according to a fourteenth aspect is a decoding device for decoding coded data, and judges whether or not the coded data includes a predetermined unique pattern, and Based on the determination result, a decoding unit (for example, the quantization accuracy information decoding unit 22 shown in FIG. 6) that decodes the encoded data by one of the first and second methods is used. It is characterized by being provided.

According to a sixteenth aspect of the present invention, the transmission apparatus selects one of the first and second methods depending on whether or not the encoding target information to be encoded satisfies a predetermined condition, An encoding unit (for example, the quantization accuracy information encoding unit 5 shown in FIG. 1) for encoding the encoding target information by the selected method is provided, and the encoded data output from the encoding unit is transmitted. In the transmission device, data obtained by encoding the encoding target information by one of the first and second methods is configured to include a predetermined unique pattern. And

Of course, this description does not mean that each means is limited to the above.

FIG. 1 shows the configuration of an embodiment of an encoding device to which the present invention is applied. Note that, in the figure, parts corresponding to those in FIG. 12 are denoted with the same reference numerals, and description thereof will be omitted below as appropriate. That is, this encoding device has the same configuration as the encoding device of FIG. 12 except that the quantization accuracy information encoding unit 5 is newly provided.

The quantizing precision information coding unit 5 is also described later according to whether the quantizing precision information output from the quantizing precision determining unit 3 satisfies a predetermined condition to be described later.
One of the two methods is selected, the quantization accuracy information is encoded by the selected method, and the resulting quantization accuracy information encoded data is output to the multiplexer 6.

FIG. 2 is a block diagram of the quantization precision information coding unit 5 of FIG.
The example of composition of is shown. The fixed quantization precision pattern storage unit 11 stores reference quantization precision information (reference information) for the first to fourth coding units. Here, the reference quantization accuracy information is for obtaining a difference from the quantization accuracy information of the first to fourth encoding units,
The difference value is determined in advance so that there is a high possibility that the difference value becomes 0 or a value close to 0.

Quantization accuracy information of the first to fourth coding units is supplied from the quantization accuracy determination unit 3 to the arithmetic units 12 _{1 to} 12 ₄ , respectively. Also,
The arithmetic units 12 _{1 to} 12 ₄ are also supplied with the reference quantization precision information of the first to fourth encoding units from the fixed quantization precision pattern storage unit 11, respectively. The calculators 12 _{1 to} 12 ₄ respectively calculate differences between the quantization accuracy information of the first to fourth encoding units and the reference quantization accuracy information of the first to fourth encoding units,
The resulting difference value (hereinafter appropriately referred to as difference quantization accuracy information) (relative information) is output to the encoding unit 13.

The encoding unit 13 includes arithmetic units 12 _{1 to} 12 ₄
The first to fourth differential quantization precision information is supplied from each of them, and the quantization precision information of the first to fourth encoding units is also supplied from the quantization precision determination unit 3. . The encoding unit 13 is configured to select either the quantization accuracy information or the difference quantization accuracy information and encode the selected information. The quantization precision information coded data obtained as a result of this coding is supplied to the multiplexer 6.

When the quantization precision information is selected, the encoding unit 13 encodes the quantization precision information by a predetermined unique pattern (here, for example, it is obtained by encoding the difference quantization precision information. The pattern does not appear in the data) is added.

FIG. 3 shows the quantization accuracy information and the quantization step (quantization step number) (the range of -1.0 to 1.0 taken by the normalized data to be quantized is divided into several steps. Do you do)). According to this relationship, when the quantization precision information is 0, all the normalized data are quantized to 0. When the quantization precision information is 1, the normalized data has a range of -1.0 to 1.0.
-1, 0, +1 divided by 3 which is the quantization step
Quantized into any of the steps. Further, when the quantization precision information is 2, the normalized data is −
The range of 1.0 to 1.0 is quantized into any one of five steps of -1, -1/2, 0, +1/2, and +1 which is divided by 5 which is a quantization step. Hereinafter, the same applies to other pieces of quantization accuracy information.

FIG. 4 shows the relationship between the difference quantization accuracy information input to the encoding unit 13 of FIG. 2 and the quantization accuracy information encoded data output from the difference quantization accuracy information. When the difference quantization precision information is 0, that is, when the quantization precision information is equal to the reference quantization precision information, the quantization precision information is 1-bit 0 ₂ (0 ₂ , 0 is a binary number). (Representing) is encoded. Also, when the difference quantization precision information is 1 or -1, the quantization precision information is 100 _{2 of} 3 bits.
Alternatively, it is encoded into data of 101 ₂ . Therefore, when the difference quantization accuracy information is any one of -1, 0, or 1, the method of encoding the difference quantization accuracy information (in other words, the method of using the reference quantization accuracy information) (first method) Method) is selected, and the quantization accuracy information is encoded by this method.

On the other hand, the difference quantization precision information is -1,0,
And if one neither, quantization accuracy information, the predetermined unique pattern 11 ₂ is encoded to that adds the quantization step information. That is, in this case, the method of encoding the quantization accuracy information itself (in other words, the method of not using the reference quantization accuracy information) (second method) is selected, and the quantization accuracy information is encoded by this method. Be converted.

Therefore, in the encoding unit 13, there are two cases, that is, the case where the quantization precision information itself is encoded and the case where the difference quantization precision information is encoded instead of the quantization precision information. When the quantization precision information itself is encoded, a unique pattern 11 ₂ (hereinafter, appropriately referred to as an escape code) is added. Therefore, the quantization precision information encoded data is based on the escape code. It is possible to recognize whether the quantization precision information itself is encoded or the difference quantization precision information is encoded.

That is, in this case, it is recognized whether the quantization precision information coded data is the quantization precision information itself or the difference quantization precision information is encoded. However, the flag described in FIG. 14 is not necessary.

Further, in FIG. 4, when the absolute value of the difference quantization precision information is small, the bit length is short, that is, when the difference quantization precision information is 0, it is 1 bit, and the absolute value of the quantization precision information is large. Sometimes with long bit length, ie
When the difference quantization precision information is 1 and -1, the quantization precision information is encoded into 3 bits. When the absolute value of the quantization precision information is larger, the quantization precision information is encoded in a form in which the quantization precision information is added to the escape code, that is, in a longer bit length. .

As described above, the reference quantization accuracy information is
Since the difference quantization accuracy information is determined so as to have a high possibility of becoming 0 or a value close to 0, the quantization accuracy obtained as a result of encoding the quantization accuracy information as described above It is possible to reduce the number of bits of information encoded data. Therefore, the data amount of the entire encoded data can be reduced, and the encoding efficiency can be improved.

Further, in this case, it is possible to deal with the case where it is necessary to change the quantization step according to the change in the property of the signal (here, the audio signal).

In FIG. 4, the quantization precision information arranged after the escape code is 3 bits. The quantization precision information is 0 to 7 as shown in FIG.
This is because it takes a value that can be represented by the range of, that is, 3 bits.

In addition, in FIG. 4, when the differential quantization precision information is encoded, not the quantization precision information itself, the difference quantization precision information is coded as either 1 or 3 bits, that is, data having a variable bit length. However, the differential quantization accuracy information can also be encoded into data having a fixed bit length. In this case, if the fixed bit length is shorter than the bit length obtained by encoding the quantization precision information itself, the information regarding the quantization precision can be encoded with a small number of bits.

However, in this case, since the degree of freedom of the quantization precision information is limited, the reference quantization precision information stored in the fixed quantization precision pattern storage unit 11 takes this into consideration. It is desirable to set a value that can ensure a certain level of sound quality.

Next, referring to the flow chart of FIG.
The operation of the quantization accuracy information encoding unit 5 in FIG. 2 will be described. From the quantization accuracy determination unit 3 to the arithmetic unit 12 ₁ ,
When the quantization accuracy information of the first encoding unit is supplied, the arithmetic unit 12 ₁ reads the reference quantization accuracy information D0 of the first encoding unit from the fixed quantization accuracy pattern storage unit 11 in step S1. Then, the difference between the quantization accuracy information Q1 of the first encoding unit and the first reference quantization accuracy information Q0 is calculated to obtain the difference quantization accuracy information D of the first encoding unit. To be And
The difference quantization accuracy information D of this first encoding unit is
It is supplied from the arithmetic unit 12 ₁ to the encoding unit 13, and in the encoding unit 13, it is determined in step S2 whether the difference quantization accuracy information D of the first encoding unit is equal to 0.

When it is determined in step S2 that the difference quantization accuracy information D of the first coding unit is equal to 0, the process proceeds to step S3, and the coding unit 13 calculates the difference quantization accuracy of the first coding unit. As described with reference to FIG. 4, the encoding accuracy information D is encoded into 0 ₂ , and further, for example, variable length encoding processing or the like is performed on this as necessary to obtain quantization accuracy information encoded data. It is output and the process is terminated.

If it is determined in step S2 that the difference quantization precision information D of the first encoding unit is not equal to 0, the process proceeds to step S4, and the encoding unit 13 determines the first encoding unit. Difference quantization accuracy information D
Is determined to be equal to 1.

When it is determined in step S4 that the difference quantization accuracy information D of the first encoding unit is equal to 1, the process proceeds to step S5, and the encoding unit 13 calculates the difference quantization accuracy of the first encoding unit. As described with reference to FIG. 4, the encoding precision information D is encoded into 100 ₂ , and further, for example, a variable length encoding process or the like is performed on this as necessary to obtain quantization precision information encoded data. It is output and the process is terminated.

If it is determined in step S4 that the difference quantization accuracy information D of the first encoding unit is not equal to 1, the process proceeds to step S6, and the encoding unit 13 determines the first encoding unit. Difference quantization accuracy information D
Is determined to be equal to -1. In step S6, the difference quantization accuracy information D of the first coding unit
When it is determined that is equal to −1, the process proceeds to step S7, and in the encoding unit 13, the difference quantization accuracy information D of the first encoding unit is 101 as described in FIG.
Coded to ₂ , and for this, if necessary,
For example, a variable length coding process is performed, the quantization accuracy information coded data is output, and the process ends.

On the other hand, if it is determined in step S6 that the difference quantization precision information D of the first coding unit is not equal to -1, that is, the difference quantization precision information D of the first coding unit is , -1, 0, or 1, the process proceeds to step S8, in which the quantization accuracy information of the first encoding unit supplied from the quantization accuracy determination unit 3 in the encoding unit 13 is as shown in FIG. As described above, the code is encoded with the escape code (11 ₂ ) added, and
On the other hand, if necessary, for example, variable length coding processing or the like is performed, the quantization accuracy information coded data is output, and the processing ends.

Regarding the quantization precision information of the second to fourth coding units, the computing units 12 _{2 to} 12 ₄ also calculate the quantization precision information of the second to fourth coding units, respectively, By performing the same processing as in the case of the quantization accuracy information of the first encoding unit described above, the quantization accuracy information encoded data is obtained.

The quantization precision information coded data output from the coding unit 13 is the multiplexer 6 as described above.
(FIG. 1), where it is multiplexed with the quantized and normalized coefficients of the first to fourth coding units to produce coded data. Then, this encoded data is transmitted via a transmission path or recorded on a recording medium 7 (FIG. 1) such as an optical disc, a magneto-optical disc, a magnetic tape, an optical card, or the like.

Next, FIG. 6 shows the configuration of an embodiment of a decoding device for decoding the encoded data output from the encoding device of FIG. Incidentally, in the figure, the same reference numerals are given to the portions corresponding to the case in FIG.
In the following, the description will be appropriately omitted.

To the demultiplexer 21, the encoded data transmitted via the transmission path or the encoded data reproduced from the recording medium 7 by a reproducing device (not shown) is input. The demultiplexer 21 separates and decodes the quantization accuracy information coded data, the quantized coefficients and the normalization coefficients of the first to fourth coding units from the coded data,
The quantization accuracy information encoded data is output to the quantization accuracy information decoding unit 22, and the quantization coefficients and normalization coefficients of the first to fourth encoding units are output to the signal component configuration units 23 _{1 to} 23 ₄ Output to each.

The quantization precision decoding unit 22 performs variable length decoding on the quantization precision information coded data, if necessary, and then determines whether or not the escape code is included therein. Further, the quantization precision decoding unit 22 selects one of the two methods based on the determination result, and decodes the quantization precision information coded data by the selected method.

That is, the quantization accuracy decoding unit 22 decodes the quantization accuracy information coded data based on the correspondence between the difference quantization accuracy information and the quantization accuracy information coded data described in FIG. To do.

Specifically, the quantization precision decoding unit 22
First, it is determined whether the first bit of the quantization accuracy information encoding data (first bit) is 0 _2, if it is 0 _2, the 0 _2, decodes the standard quantization accuracy information.

Further, if the first bit of the quantization precision information coded data is 1 ₂ , the quantization precision decoding unit 22
It is determined whether or not the second bit (the second bit from the beginning) is 0 ₂ . Then, the quantization accuracy decoding unit 2
2 indicates that the second bit of the quantization precision information coded data is 0 ₂
, It is determined whether the third bit is 0 ₂ . The third bit of the quantization precision information encoded data is 0
_In the case of ₂ , the quantization precision encoding unit 22 decodes the quantization precision information encoded data into a value obtained by adding 1 to the reference quantization precision information. When the third bit of the quantization precision information encoded data is 1 ₂ , the quantization precision encoding unit 22 obtains a value obtained by subtracting 1 from the reference quantization precision information on the quantization precision information encoded data. Decrypt to.

Therefore, when the first bit of the quantization precision information coded data is 0 ₂ , and when the first to third bits thereof are 100 ₂ and 101 ₂ , the quantization precision information decoding unit 22 sets the reference A method (first method) using the quantization accuracy information is selected, and the quantization accuracy information encoded data is decoded by that method.

On the other hand, the first of the quantization precision information coded data
If the bit is not 0 ₂ and the second bit is not 0 ₂ , that is, the first and second bits of the quantization precision information encoded data are 11 ₂ , that is, escape to the quantization precision information encoded data. When the code is included, the quantization precision information decoding unit 22 decodes the quantization precision information coded data into 3-bit data of the third to fifth bits, that is, 3-bit data following the escape code. Turn into. Therefore, when the quantization accuracy information encoded data includes an escape code, the quantization accuracy information decoding unit 22 does not use the reference quantization accuracy information (second method).
Is selected, and the quantization precision information coded data is decoded by that method.

Quantization accuracy information of the first to fourth encoding units obtained by performing the above decoding processing in the quantization accuracy information decoding unit 22 includes signal component forming units 23 _{1 to} 23 _1. 23 ₄ , respectively. Then, hereinafter, as in the case described above, the signal components forming sections 23 _{1 to} 23 ₄ decode the signals of the first to fourth encoding units, respectively, and further, in the band synthesizing section 24, the first to fourth The original audio signal is restored by synthesizing the signals of the four coding units.

FIG. 7 shows the quantization accuracy information decoding unit 2 of FIG.
2 shows a configuration example of No. 2. The decoding unit 31 is supplied with the quantization precision information coded data from the demultiplexer 21. The decoding unit 31 performs variable-length decoding on the quantization precision information coded data for the first to fourth coding units, if necessary, and then, a value corresponding to the quantization precision information coded data. Is output to the arithmetic units 32 _{1 to} 32 ₄ . The arithmetic units 32 _{1 to} 32 ₄ add the output of the decoding unit 31 as it is, or add the output of the decoding unit 31 and the value stored in the fixed quantization precision pattern storage unit 33 to obtain the quantization precision information. It is designed to be output as. The fixed quantization precision pattern storage unit 33 stores the same reference quantization precision information of the first to fourth coding units as in the fixed quantization precision pattern storage unit 11 of FIG. The data is output to the arithmetic units 32 _{1 to} 32 ₄ .

Next, referring to the flow chart of FIG.
The operation will be described. When the decoding unit 31 receives from the demultiplexer 21 the quantization accuracy information coded data for the first coding unit, the step S
At 11, it is determined whether the first bit b1 is equal to 0 ₂ . When it is determined in step S11 that the first bit b1 of the quantization accuracy information encoded data for the first encoding unit is equal to 0 ₂ , the process proceeds to step S12, and the decoding unit 31 causes the arithmetic unit 32 ₁ In response to the fixed quantization precision pattern 33
And the reference quantization precision Q0 of the first encoding unit stored in. Then, the addition result in the arithmetic unit 32 ₁ is output as the first quantization accuracy information Q1, and the processing is ended. Therefore, in this case, the reference quantization precision Q0 of the first coding unit is directly output as the first quantization precision information Q1.

If it is determined in step S11 that the first bit b1 of the quantization precision information coded data for the first coding unit is not equal to 0 ₂ ,
In step S13, the decoding unit 31 determines whether the second bit b2 is equal to 0 ₂ . In step S13, the second bit b2 of the quantization accuracy information coded data for the first coding unit is 0 ₂
When it is determined that the third bit b3 is equal to 0 ₂ , the decoding unit 31 determines whether the third bit b3 is equal to 0 ₂ .

When it is determined in step S14 that the third bit b2 of the quantization precision information coded data for the first coding unit is equal to 0 ₂ , that is, the first bit
If the first to third bits of the quantization precision information coded data for the coding unit of 100 are 100 ₂ , the decoding unit 31 outputs ₁ to the arithmetic unit 32 ₁ , In addition, the fixed quantization precision pattern 33
And the reference quantization precision Q0 of the first encoding unit stored in. Then, the addition result in the arithmetic unit 32 ₁ is output as the first quantization accuracy information Q1, and the processing is ended. Therefore, in this case, a value (Q0 + 1) obtained by adding 1 to the reference quantization precision Q0 of the first coding unit is output as the first quantization precision information Q1.

If it is determined in step S14 that the third bit b2 of the quantization precision information coded data for the first coding unit is not equal to 0 ₂ ,
That is, when the first to third bits of the quantization accuracy information coded data for the first coding unit are 101 ₂ , the process proceeds to step S16, and the decoding unit 31 causes the arithmetic unit 3
To 2 _1, and it outputs a -1, therewith, is added to the reference quantization accuracy Q0 of the first encoding unit stored in the fixed quantization accuracy pattern 33. And the arithmetic unit 32
The addition result of ₁ is output as the first quantization accuracy information Q1, the process ends. Therefore, in this case, the first
A value (Q0-1) obtained by subtracting 1 from the reference quantization accuracy Q0 of the first coding unit is output as the quantization accuracy information Q1 of Q1.

On the other hand, if it is determined in step S13 that the second bit b2 of the quantization precision information coded data for the first coding unit is not equal to 0 ₂ ,
That is, when the first and second bits of the quantization accuracy information encoded data for the first encoding unit are the escape code (11 ₂ ), the process proceeds to step S17, and the decoding unit 31 determines the first code. The 3-bit data of the third to fifth bits of the quantization precision information coded data for the quantization unit is directly output as the first quantization precision information Q1 via the arithmetic unit 32 ₁ and the process ends. To do. That is, in this case, the first quantization precision information Q1 is the first
Of the quantization accuracy information encoded data of the encoding unit of
3-bit data represented by the bit b3, the fourth bit b4, and the fifth bit b5 is output.

Similarly, the quantization precision information coded data of the second to fourth coding units are similarly decoded into the quantization precision information of the second to fourth coding units (however, The arithmetic units 32 _{2 to} 32 ₄ are used for decoding the quantization accuracy information encoded data of the second to fourth encoding units).

As described above, among the quantization accuracy information, the unique pattern is included in the information that is encoded without using the reference quantization accuracy information.
In the decoding device, it is possible to recognize whether the encoding is performed using the reference quantization accuracy information or not, and as a result, the quantization accuracy information encoded data is accurately stored, It can be decoded into quantization accuracy information.

Next, FIG. 9 shows another example of the configuration of the quantization precision information coding unit 5 of FIG. Note that, in the figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals. That is, the quantization precision information coding unit 5 is provided with a standard quantization precision pattern calculation unit 41 in place of the fixed quantization precision pattern storage unit 11, except that the quantization precision information coding unit of FIG. It has the same configuration as the unit 5.

The standard quantization precision pattern calculation unit 41 has
The normalization coefficients of the first to fourth encoding units are supplied (from the normalization units 2 _{1 to} 2 ₄ respectively). In the standard quantization accuracy pattern calculation unit 41, the first quantization accuracy pattern calculation unit 41 calculates the first
To the fourth difference quantization precision information, the first to fourth reference quantization precision information such that the probability that the difference quantization precision information becomes 0 or a value close to 0 becomes higher, and is calculated by the calculators 12 _{1 to} 12 ₄ . Each is supplied.

Therefore, in this case, the first to fourth differential quantization accuracy information are concentrated near 0 with higher frequency, and as a result, the coding efficiency can be further improved.

FIG. 10 shows a configuration example of the quantization precision information decoding unit 22 of FIG. 6 when the quantization precision information coding unit 5 is configured as shown in FIG. In the figure, the same reference numerals are given to portions corresponding to the case in FIG. That is, this quantization accuracy information decoding unit 22
Is provided with a standard quantization precision pattern calculation unit 51 instead of the fixed quantization precision pattern storage unit 33,
It is configured similarly to the quantization accuracy information decoding unit 22 of FIG.

The standard quantization accuracy pattern calculation unit 51 has
The normalization coefficients of the first to fourth encoding units are supplied (from the demultiplexer 21).
In the standard quantization accuracy pattern calculation unit 51, the first to fourth
Based on the normalization coefficient encoding units, in the same manner as in the standard quantization accuracy pattern calculation section 41 of FIG. 9, the reference quantization step information of the first to fourth is calculated, the computing unit 32 ₁ through 32 ₄ are respectively supplied.

Therefore, also in this case, the first to fourth quantization precision information encoded by the quantization precision information encoding unit 5 in FIG. 9 can be accurately decoded.

As described above, the escape code is included in the quantization precision information coded data only when the quantization precision information is encoded without using the reference quantization precision information. Whether or not the accuracy information is encoded using the reference quantization accuracy information can be recognized without the flag as described above. Furthermore, since the frequency of the difference quantization precision information is increased to around 0, the quantization precision information is often encoded to a short code length using the reference quantization precision information. Therefore, in this case, the coding efficiency can be further improved as compared with the case where the flag is used.

In this embodiment, as the reference quantization precision information, a predetermined one or one obtained from the normalization coefficient is used. It is possible to use the quantization accuracy information of other blocks such as the previously-encoded quantization accuracy information of the block (frame).

For the most part, the spectral structure of an audio signal does not change rapidly with time, so
The quantization accuracy information also hardly changes. Therefore, when, for example, the quantization accuracy information of the previously encoded block is used as the reference quantization accuracy information, the difference quantization accuracy information is concentrated around 0, as in the above case. Therefore, also in this case, the coding efficiency can be improved.

In this embodiment, the quantization precision information is
I tried to encode using escape code,
For other normalization factors, such as normalization factors, a predetermined standard value (standard information) (hereinafter, referred to as a standard normalization factor) is used, and the normalization factor itself or the normalization factor and the standard normalization factor are used. Difference value with the coefficient (hereinafter, as appropriate
It is possible to select and encode any one of the difference normalization coefficients).

In this case, the relationship between the differential normalization coefficient and the normalization coefficient coded data obtained as a result of the coding can be set as shown in FIG. 11, for example. That is, in this case, the difference normalization coefficient is 3, 2, 1, 0, -1, -2,
When a -3 (when the absolute value of the difference normalization factor is 3 or less), the normalization factor, respectively 011 _2, 01
0 _2, 001 _2, 000 _2, are 111 _2, 110 _2, 101 encoded into data of _two of the 3-bit fixed-length. Also,
The difference normalization coefficient is 3,2,1,0, -1, -2, -3
If neither of the above is true, the normalization coefficient is encoded as data in which the normalization coefficient itself is added to the escape code.

In the embodiment shown in FIG. 11, the escape code is 011 ₂ , 010 ₂ , 001 ₂ , 2,000 ₂ , 111.
_2, 110 _2, 101 ₂ are the 3-bit data 100 ₂ none. The normalization coefficient is given by 6 bits. Furthermore, in the embodiment of FIG. 11, when the absolute value of the difference normalization coefficient is 3 or less, the normalization coefficient is encoded into 3-bit fixed-length data. Similar to the case of the quantization accuracy information described above, it is also possible to encode into data having a variable bit length.

By encoding the normalization coefficient as described above, the overall coding efficiency can be improved (the normalization coefficient must be coded by adding an escape code to the normalization coefficient. In particular, the coding efficiency can be improved when some coding units are distributed).

Further, in this embodiment, the quantization accuracy information and the normalization coefficient, which are the sub-information, are encoded by using the escape code. However, in addition to this, for example, the audio which is a direct encoding target is encoded. The signal can also be encoded using the escape code.

That is, for example, using the previous quantized coefficient or the like, either the quantized coefficient itself or the difference value between the quantized coefficient and the previous quantized coefficient is selected and encoded. For example, when encoding the quantized coefficient itself, it is possible to add an escape code.

Furthermore, in the present embodiment, when encoding is performed using the reference quantization accuracy information, the encoding is performed based on the difference quantization accuracy information obtained by subtracting the reference quantization accuracy information from the quantization accuracy information. However, it is also possible to perform encoding based on, for example, a ratio (relative information) between the quantization accuracy information and the reference quantization accuracy information.

The present invention can also be used in combination with the flag described in FIG. That is,
For example, prepare a flag for each block or group that indicates whether or not to use the escape code for encoding, and for the block or group for which the flag is set, perform the encoding using the escape code so that the flag It is possible to encode the quantization accuracy information (or the difference quantization accuracy information) in a block or a group that does not exist. In this case, the flag control may be performed, for example, so that the overall coding efficiency becomes higher.

Further, although the present embodiment has been described by taking the case of encoding an audio signal as an example, the present invention can be applied to the case of encoding any other signal such as a video signal. It is possible. In addition,
For signals with high correlation between blocks (frames) such as audio signals, the change in normalization coefficient or quantization accuracy information between blocks is usually small, and therefore reference information (reference normalization coefficient or reference quantization Since the difference value with respect to the accuracy information) is often coded (the escape code is less often added), the information can be compressed particularly effectively.

Further, in the present embodiment, the escape code is added when the quantization precision information is encoded without using the reference quantization precision information. It is also possible to use the quantization precision and add it when encoding the quantization precision information.

Further, in the present embodiment, as described with reference to FIG. 4, for example, when the absolute value of the difference quantization precision information is 1 or less, the encoding is performed by the method using the reference quantization precision information, and the absolute value is calculated. When the value is larger than 1, the encoding is performed by the method that does not use the reference quantization accuracy information. However, which of the method that uses the reference quantization accuracy information and the method that does not use the reference quantization accuracy information is selected is, for example, It is possible to make a decision depending on which of these methods results in higher overall coding efficiency. That is, for example, both the method using the reference quantization accuracy information and the method not using the reference quantization accuracy information, once encoded, based on the encoding result, the usage using the reference quantization accuracy information, or, It is possible to determine whether to perform encoding by a method that does not use the reference quantization accuracy information.

Further, the number of bits to be assigned to the data obtained as a result of encoding by the method using the reference quantization precision information needs to be limited to a small value so as to improve the encoding efficiency. Therefore, for example, the data obtained as a result of encoding by the method using the reference quantization accuracy information is
If it is within such a bit number, select the method that uses the reference quantization precision information, and if it is larger than such bit number, select the method that does not use the reference quantization precision information. It is also possible to do so.

Further, in the present embodiment, the escape code is arranged at the beginning of the quantization precision information coded data, but the escape code can be arranged at other positions.

[0136]

According to the encoding device described in claim 1 and the encoding method described in claim 13, and the transmission device described in claim 16 and the transmission method described in claim 17,
Either the first or the second method is selected depending on whether or not the coding target information to be coded satisfies a predetermined condition, and the coding target information is coded by the selected method. Be converted. Then, the encoding target information is
The data obtained by encoding with either one of the first and second methods is configured to include a predetermined unique pattern. Therefore, it is possible to recognize which of the first and second methods has been used for encoding by a predetermined unique pattern, so that the first or second method can be used to further improve the encoding efficiency. Second
Flexible choice of one of the
It becomes possible to perform encoding.

According to the decoding device of the fourteenth aspect and the decoding method of the fifteenth aspect, it is determined whether or not the coded data includes a predetermined unique pattern, and the determination result Based on the above, the encoded data is decoded by one of the first and second methods. Therefore, as described above, it is possible to decode the encoded data that has been encoded so that the encoding efficiency is improved.

In the recording medium according to the eighteenth aspect, either the first method or the second method is selected depending on whether the encoding target information to be encoded satisfies a predetermined condition. The information to be encoded is encoded by the selected method, and the encoded data obtained as a result is recorded. Then, the data obtained by encoding the encoding target information by one of the first and second methods is configured to include a predetermined unique pattern. Therefore, it becomes possible to record more information.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an encoding device to which the present invention has been applied.

2 is a block diagram showing a configuration of a first embodiment of a quantization accuracy information encoding unit 5 in FIG.

FIG. 3 is a diagram showing a relationship between quantization accuracy information and a quantization step.

FIG. 4 is a diagram showing a relationship between difference quantization accuracy information and quantization accuracy information encoded data.

5 is a flowchart for explaining the operation of the quantization accuracy information encoding unit 5 in FIG.

FIG. 6 is a block diagram showing the configuration of an embodiment of a decoding device to which the present invention has been applied.

7 is a block diagram showing a configuration of a first embodiment of a quantization accuracy information decoding unit 22 of FIG.

8 is a block diagram for explaining an operation of the quantization accuracy information decoding unit 22 in FIG.

9 is a block diagram showing a configuration of a second embodiment of the quantization accuracy information encoding unit 5 in FIG.

10 is a block diagram showing a configuration of a second embodiment of the quantization accuracy information decoding unit 22 of FIG.

FIG. 11 is a diagram showing a relationship between difference normalization coefficients and normalization coefficient encoded data.

FIG. 12 is a block diagram showing a configuration of an example of a conventional encoding device.

FIG. 13 is a block diagram showing a configuration of an example of a conventional decoding device.

FIG. 14 is a diagram for explaining a conventional method of encoding sub information.

[Explanation of symbols]

1 Band Division Unit 2 _{1 to} 2 ₄ Normalization Unit 3 Quantization Precision Determination Unit 4 _{1 to} 4 ₄ Quantization Unit 5 Quantization Precision Information Encoding Unit 6 Multiplexer 11 Fixed Quantization Precision Pattern Storage Unit 12 _{1 to} 12 ₄ Calculation Device 13 Encoding unit 21 Demultiplexer 22 Quantization accuracy information decoding unit 23 _{1 to} 23 ₄ Signal component configuration unit 24 Band combining unit 31 Decoding unit 32 _{1 to} 32 ₄ Operator 33 Fixed quantization accuracy pattern storage unit 41, 51 Standard Quantization Accuracy Pattern Calculation Unit

Claims (18)

[Claims] 1. Depending on whether or not the coding target information to be coded satisfies a predetermined condition, either one of the first and second methods is selected, and the code is selected by the selected method. Data obtained by encoding the encoding target information by one of the first and second methods is provided with a predetermined unique pattern. An encoding device comprising: 2. The encoding means, when performing encoding by the first method, extracts predetermined relative information from the encoding target information, encodes the relative information, and executes the second method. The encoding device according to claim 1, wherein the encoding target information itself is encoded when the encoding is performed by the method. 3. The encoding apparatus according to claim 2, wherein the relative information is a difference between the encoding target information and predetermined reference information. 4. The encoding apparatus according to claim 3, wherein the reference information is encoding target information encoded last time. 5. The encoding apparatus according to claim 1, wherein the encoding target information relates to a quantization step used when quantizing predetermined data. 6. The encoding device according to claim 5, wherein the predetermined data is an audio signal. 7. The encoding apparatus according to claim 1, wherein the encoding target information is a normalization coefficient used when normalizing predetermined data. 8. The encoding device according to claim 7, wherein the predetermined data is an audio signal. 9. The encoding device according to claim 2, wherein the encoding means encodes the relative information into data having a fixed code length. 10. The encoding means includes the relative information,
The encoding device according to claim 2, wherein the encoding device encodes data having a variable code length. 11. The encoding means selects one of the first and second methods, whichever has a higher encoding efficiency when the object to be encoded is encoded.
An encoding device according to claim 1. 12. The data obtained by encoding the encoding target in the first or second method when the number of bits assigned to the encoding target is fixed. 2. The encoding apparatus according to claim 1, wherein one that is within the number of bits is selected. 13. The first or the second, depending on whether or not the encoding target information to be encoded satisfies a predetermined condition.
Of the first or second method, which is a coding method for selecting one of the above methods and coding the coding target information by the selected method. An encoding method characterized in that data obtained by encoding with one of the methods is configured to include a predetermined unique pattern. 14. A decoding device for decoding encoded data, wherein it is determined whether the encoded data includes a predetermined unique pattern, and the code is determined based on the determination result. A decoding device comprising a decoding means for decoding the encrypted data by either one of the first and second methods. 15. A decoding method for decoding encoded data, comprising: determining whether or not the encoded data includes a predetermined unique pattern, and determining the code based on the determination result. A decoding method, characterized in that the encrypted data is decoded by one of the first and second methods. 16. The first or the second depending on whether or not the encoding target information to be encoded satisfies a predetermined condition.
In a transmission device that includes any one of the above methods, includes a coding unit that codes the coding target information by the selected method, and that transmits the coded data output from the coding unit. The data obtained by encoding the encoding target information by any one of the first and second methods is configured to include a predetermined unique pattern. Transmission equipment. 17. The first or the second depending on whether or not the encoding target information to be encoded satisfies a predetermined condition.
A method of selecting one of the methods, encoding the encoding target information by the selected method, and transmitting the encoded data obtained as a result, wherein the encoding target information is: A transmission method characterized in that data obtained by encoding by one of the first and second methods is configured to include a predetermined unique pattern. 18. The first or the second depending on whether or not the encoding target information to be encoded satisfies a predetermined condition.
Of one of the methods, the encoding method by the selected method, the recording medium in which the encoded data obtained as a result is recorded, the encoding target information The recording medium characterized in that the data obtained by encoding by any one of the first and second methods is configured to include a predetermined unique pattern.