JP2003218701A - Coding apparatus, decoding apparatus and system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decoding apparatus which eliminates the unreasonable need for having audience to always view at a high quality level. <P>SOLUTION: The decoding apparatus 30a comprises: a narrow-band decoder 31 for regenerating a PCM signal P<SB>1</SB>based on a narrow-band bit stream contained in a broadband bit stream S<SB>0</SB>; a broadband decoder 32 for regenerating a PCM signal P<SB>2</SB>having a band broader than the PCM signal P<SB>1</SB>regenerated by the narrow-band decoder 31 based on the narrow-band bit stream contained in the broadband bit stream S<SB>0</SB>and a band-expanded bit stream; and a selector 34 for selecting and outputting either the PCM signal P<SB>1</SB>or P<SB>2</SB>regenerated by the narrow-band or broadband decoders 31, 32, respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal encoding / decoding process, and more particularly to an encoding device and a decoding device for generating a format of encoded data for facilitating the decoding process. The present invention relates to a device and a system using them.

[0002]

2. Description of the Related Art In order to meet the demand for listening to music easily, various techniques have been developed in recent years for compressing and encoding audio signals such as voices and musical tones at a low bit rate and decompressing and decoding them during reproduction. MP as a typical method
There is a system of EG standard AAC (hereinafter, abbreviated as "AAC") (see Non-Patent Document 1).

[0003]

[Non-Patent Document 1] M. Bosi et al., "IS 1381.
8-7 (MPEG-2 Advanced Audio)
Coding, AAC) ", April 1997 FIG. 18 is a diagram showing frequency bands encoded by the AAC method.

However, the higher the compression rate is, the lower the upper limit frequency of the reproduction band is, and the high frequency band is completely eliminated. The reason for this is that as the compression rate increases, not enough bits are allocated for encoding in the high frequency region, and the upper limit of the reproduction band decreases.

Therefore, in order to compensate for such a lack of high frequencies, in recent years MPEG4 Ver. In the standardization work of No. 3, the technical development and standardization of the pseudo wide band are in progress. The technique is, for example, as shown in FIG. 19, using analog information of a narrow band, that is, information of a low band to analogize and supplement information of a high band. The use of such a technology that achieves a wide band makes it possible to listen to high-quality music or listen to news on a battery-operated mobile phone or the like.

[0006]

However, it is wasteful to always watch in high quality. That is, when viewing news or the like, there is little demand from a user who requests audio reproduction in which a pseudo wide band is achieved, and there is no practical benefit of performing a pseudo wide band process in a decoding device. In addition, the pseudo wide band processing performed by the decoding device without the user's request results in wasting battery power of a mobile phone or the like equipped with the decoding device.

The present invention has been made in view of the above circumstances, and it is a first object of the present invention to provide a decoding device capable of eliminating the irrationality of constantly watching in high quality. .

A narrow band sound digital signal (hereinafter,
Also referred to as "PCM signal". It is a second object of the present invention to provide a decoding device capable of reducing the waste of battery power when reproducing (1).

A third object of the present invention is to provide an encoding device and system that facilitates the achievement of the first and second objects.

[0010]

In order to achieve the above-mentioned first object, a decoding device according to the present invention comprises a first bit stream obtained by encoding a sound digital signal and a reproduction band of the sound digital signal. A decoding device for decoding a coded signal composed of a second bit stream obtained by coding band extension information for expanding the video signal, the first bit stream based on the first bit stream included in the coded signal, First reproducing means for reproducing a digital signal of one sound, and first reproducing means for reproducing by the first reproducing means on the basis of the first bit stream and the second bit stream included in the encoded signal.
Second reproducing means for reproducing a digital signal of a second sound having a wider band than that of the digital signal of sound, a digital signal of the first sound reproduced by the first reproducing means and a second signal reproduced by the second reproducing means. And a selecting means for selecting and outputting any of the digital sound signals.

In this case, the decoding device further comprises mode setting means for notifying the selecting means of mode information designating either the first mode or the second mode,
When the mode information notified from the mode setting means indicates the first mode, the selecting means selects and outputs the digital signal of the first sound reproduced by the first reproducing means, and outputs the second mode. In the case of, the digital signal of the second sound reproduced by the second reproducing means may be selected and output.

Further, the first reproduction means converts the first bit stream separated from the encoded signal into the first bit stream and the first bit stream separated by the first separation means into an intermediate signal. A second conversion unit that converts the intermediate signal obtained by the conversion in the first conversion unit into a digital signal of the first sound;
The reproducing means has second separating means for separating the second bit stream from the encoded signal, and the band expansion information contained in the second bit stream separated by the second separating means and the first converting section. Is used to reproduce the digital signal of the second sound by using the intermediate signal obtained by the conversion of
The second reproducing means may further include information indicating a frequency spectrum, and the second reproducing means may further generate the frequency spectrum from the information of the frequency spectrum obtained by the first conversion unit according to the band expansion information. A wideband spectrum generation unit that generates a frequency spectrum in a band wider than the band, and a wideband sound that generates a digital signal of the wideband sound from the generated frequency spectrum and the frequency spectrum obtained by the first conversion unit. And a digital signal generating section, and the decoding device further notifies the selection means of mode information designating either the first mode or the second mode. When the mode information notified from the mode setting means indicates the first mode, the selecting means includes: 1 selects and outputs the digital signal of the reproduced sound reproduction means, to indicate a second mode,
A configuration may be adopted in which the digital signal of the sound reproduced by the second reproducing means is selected and output.

Further, in order to achieve the second object, the decoding apparatus according to the present invention further comprises the mode setting means,
Furthermore, the mode information is notified to the second reproducing means,
The second reproduction means stops reproduction from the second bit stream to the digital signal of the second sound when the mode information notified from the mode setting means indicates the first mode. Alternatively, the mode setting means further notifies the second reproduction means of the mode information, and the second reproduction means generates the frequency spectrum by the wideband spectrum generation section and digitalizes the second sound. At least one of the generation of the digital signal of the second sound by the signal generation unit may be stopped.

Further, the first bit stream and the second bit stream are alternately multiplexed for each predetermined frame, and the second reproducing means outputs the second bit stream from the encoded signal. The second bit stream is configured to have a second separating unit for separating, the code amount of the band expansion information is variable for each frame, and the second bit stream has size information indicating the size of the code amount. Are multiplexed, and the second separating means is
The second bitstream is separated from the encoded signal based on the size information included in the second bitstream, or the size information is arranged at the head of the second bitstream. The second demultiplexing unit specifies the size of the code amount of the band expansion information from the size information included at the head of the second bitstream, and based on the specified size, the second separation unit from the encoded signal. The bit stream is separated, or the size information is N bits indicating the size of the code amount of the band expansion information, or (N +
M) bits, and the second separation unit specifies the size of the code amount of the band expansion information from the N or (N + M) bits included at the beginning of the second bit stream,
The second bit stream is separated from the coded signal based on the specified size, or N bits in the (N + M) bits are N bits.
A bit may represent a maximum value that can be expressed, and the M bit may indicate a size of a code amount that exceeds the size indicated by the maximum value in the code amount of the band extension information.

Furthermore, the encoding device of the present invention is an encoding device for encoding a digital signal of sound, and a first encoding means for encoding the inputted digital signal of sound, and the input device. A second encoding unit that generates and encodes band expansion information for expanding the reproduction band of the signal encoded by the first encoding unit from the digital sound signal, and the second encoding unit. Size calculation means for calculating the size of the obtained coded signal; first multiplexing for multiplexing the information indicating the size calculated by the size calculation means and the coded signal obtained by the second coding means And a second multiplexing means for multiplexing the first bit stream obtained by the first encoding means and the second bit stream obtained by the first multiplexing means. And

Here, the second multiplexing means is the first multiplexing means.
The bit stream and the second bit stream are alternately multiplexed for each predetermined frame, or the first multiplexing means has information indicating the size of the second bit stream. The information indicating the size and the encoded signal are multiplexed so as to be arranged at the head, and the size information is N bits indicating the size of the code amount of the band expansion information. , Or (N + M) bits, and the size calculating means determines whether the size of the code amount of the band expansion information is less than the maximum value represented by N bits or not. It is characterized by deciding which of the bits to use, or N in the (N + M) bits.
The bit indicates the maximum value that N bits can represent, and the M
The bit may indicate the size of the code amount that exceeds the size indicated by the maximum value in the code amount of the band expansion information.

The present invention can be realized as a communication system including the encoding device and the decoding device, or a code having steps that are characteristic means of the encoding device, the decoding device, and the communication system. Encryption method, decryption method,
It can be realized as a communication method, can be realized as an encoding program or a decoding program that causes a CPU to execute the characteristic means or steps configuring the encoding device and the decoding device, or can encode a digital signal of the first sound. A computer recorded with an encoded signal in which the first bit stream and the second bit stream in which the band expansion information for expanding the reproduction band of the digital signal of the second sound are encoded are multiplexed for each frame. Needless to say, it can be realized as a readable recording medium.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An encoding apparatus, a decoding apparatus and a system using them according to the present invention will be sequentially described below with reference to the drawings.

(Embodiment 1) First, an encoding apparatus that facilitates achievement of the first and second objects in the decoding apparatus will be described.

An encoding apparatus according to the first embodiment of the present invention will be described below with reference to the drawings. Figure 1
3 is a block diagram showing a functional configuration of the encoding device 10 according to the first embodiment. FIG.

The encoding device 10 includes a narrow band encoding unit 1
1, a band expansion coding unit 12, a code amount calculation unit 13, a code amount multiplexing unit 14, and a stream multiplexing unit 15.

The narrow band coding unit 11 receives the input PCM.
Frame the signal (in AAC, 1024 of the acoustic data string)
Each sample) is encoded to generate a low band narrow band bit stream S1.

The band expansion coding unit 12 receives the input PC
Band expansion information for expanding the reproduction band of the reproduction signal is acquired based on the M signal, and the acquired band expansion information is encoded for each frame to generate a high band band expansion information bit stream S21.

The code amount calculation unit 13 includes a band expansion coding unit 1
Band expansion information bit stream S21 output from
The code amount (size) L of is calculated for each frame. The code amount multiplexing unit 14 multiplexes the signal determined based on the code amount L and the output signal of the band expansion encoding unit 12 to generate a high band band expansion bit stream S2 (= L + S2).
1) is generated.

The stream multiplexing unit 15 outputs the narrow band bit stream S1 output from the narrow band coding unit 11.
And the band expansion bit stream S2 output from the code amount multiplexing unit 14 are multiplexed for each frame to generate a wide band bit stream S0.

Each unit constituting such an encoding device 10 provides a CPU, a ROM for storing a program executed by the CPU, a work area when the program is executed, and a sound of an input PCM signal. It is realized by a memory or the like that temporarily stores data and the like.

The operation of the coding apparatus 10 having such a configuration will be described with reference to the flowchart shown in FIG. First, the narrow band encoding unit 11 encodes the input PCM signal for each frame, and outputs the narrow band bit stream S
1 is generated (S11).

Here, the narrow band bit stream S1 is
For example, it is a bit stream of the MPEG standard AAC system. That is, the frequency band of the signal encoded here is, for example, the portion surrounded by the solid line α in FIG. 18 (ISO / IEC 13818-7: 199).
7. ).

Next, the band expansion coding unit 12 codes the band expansion information for expanding the reproduction band of the reproduction signal for each frame (S12). In the reproduction of only the frequency band of the portion α surrounded by the solid line in FIG. 18, since the signal in the high frequency region is missing, information for compensating for this is extracted and encoded. For example, by analogy with the information in the high frequency region from the signal in the frequency region surrounded by the solid line in FIG.
Encode information for compensation. An area β surrounded by a dotted line in FIG. 19 corresponds to this.

Next, the code amount calculation unit 13 calculates the code amount (size) L for each frame output from the band expansion encoding unit 12 in units of bytes (S13). FIG. 3 is FIG.
FIG. 4 is a diagram showing the details of the processing executed when the code amount calculated in step S13 of FIG. 4 is multiplexed into the band extension bit stream S2, and FIG. 4 shows the length of the bit stream created by the processing shown in FIG. It is a figure which shows an example of a structure of the size information L. In addition, in FIG. 4A, the length information L is formed only by an N-bit bit field (size_of_ext).
4B shows the case where the length information L is composed of two N-bit bit fields (size_of_ext) and M-bit additional bit fields (size_of_esc). Shows.

There are two cases as described above, since the code amount of the band expansion information is variable for each frame, the length information (code amount) L cannot be expressed only by the N-bit bit field (size_of_ext). Sometimes,
N-bit bit field (size_of_ex
In case the code amount L cannot be represented only by t), an additional M-bit bit field (size_of_es) is added.
This is because c) is required.

For example, when N is 4 bits, the code amount L is 1
When the length is 4 bytes or less, 14 (0x1) is set by using this 4-bit bit field (size_of_ext).
110) is expressed. In this case, the N-bit bit field (size_of_ext) is ((1 << N)-
1) That is, since it is not “0x1111”, there is no additional bit field (size_of_esc). On the other hand, when the code amount L is 15 or more, a maximum value of 15 (0x1111) is first expressed using a 4-bit field to express that the code amount L is 15 bytes or more, and then M bits. Additional fields for (siz
e_of_esc) is used to represent 15 or more parts. For example, if the code amount L is 20 bytes, an N-bit bit field (size_of_e
xt) is “0x1111”, and the M-bit additional bit field (size_of_esc) is “0x000000101” when M is 8 bits.

If both N and M are 8 bits and the value of the size information is 128 bytes, the N-bit bit field (size_of_ext) is b'1000.
0000, and size_of_ext becomes ((1 <
<N) -1), that is, not b'11111111, so an additional M bit bit field (size_o)
f_esc) does not exist. Next, for example, when the value of the size information is 257 bytes, the N-bit bit field (size_of_ext) is set to b'1111.
1111 and the value of size_of_esc is b'00000010.

By doing so, when the value of the size information is smaller than 255 bytes, it is represented by only 8 bits, and when it is 255 bytes or more, (255+
The value of γ) is further represented by 8 bits.

Next, the code amount multiplexing unit 14 detects the signal determined based on the code amount L and the band expansion encoding unit 1.
The output signal of 2 is multiplexed and the band expansion bit stream S2 is generated (S14).

Finally, the stream multiplexer 15 multiplexes the narrow band bit stream output from the first encoder and the band expansion bit stream output from the first multiplexer for each frame. (S15).

As a result, for example, as shown in FIG.
A coded signal (wideband bitstream S0) in which the narrowband bitstream S1 and the wideband bitstream S2 are multiplexed for each frame is formed.

The formed encoded signal has a block structure. Each block stores the data of the multiplexing unit of the narrow band bit stream S1 or the band expanding bit stream S2, respectively.

In this embodiment, the data of the multiplexing unit is the audio data of one frame, but the data may be of a predetermined number of frames such as 2 frames and 3 frames.

In the block next to the block storing the frame data of the narrow band bit stream, the frame data of the corresponding band expanding bit stream is stored.
In addition, as shown in FIG.
The length information L calculated by the code amount calculation unit 13 is stored in a portion (for example, a header portion) surrounded by the thin line.

Here, the length information L is information for the decoding device to determine the end position of the block storing the data of the band expansion bit stream. If the decoding device can determine the end position, the information is not limited to this, and for example,
It may be position information of the end of the block starting from the beginning of the wideband bitstream. Also, it is of course possible to substitute by indicating the head position of the next block.

In this embodiment, the length information L is
Although it is assumed that the stream is stored as a part of the band expanding bitstream, it may be a stream different from the band expanding bitstream.

Therefore, the narrow band bit stream S1
Can be decoded together with the band extension bit stream S2, or only the narrow band bit stream S1 can be decoded except for the band extension bit stream S2.

As described above, according to the encoding device 10 of the first embodiment, in order to expand the reproduction band of the reproduction signal, the narrow band encoding unit 11 which encodes the input PCM signal for each frame. A band expansion encoding unit 12 that encodes the band expansion information for each frame, and a code amount calculation unit 13 that calculates the code amount (length information L) for each frame output from the band expansion encoding unit 12. A code amount multiplexing unit 14 that multiplexes a signal (length information L) determined based on the code amount and an output signal (band expansion information S21) of the band expansion encoding unit 12.
And a stream multiplexing unit 15 that multiplexes the narrowband bitstream S1 output from the narrowband encoding unit 11 and the band expansion bitstream S2 output from the code amount multiplexing unit 14 for each frame. As a result, since the band expansion bit stream includes information indicating the length in the encoded signal, the decoding device described below processes the narrow band bit stream S1 for each frame and then expands the band expansion bit stream S2. The processing of the narrow band bit stream S1 of the next frame can be skipped and the processing amount can be significantly reduced in the decoding processing in the mode in which the wide band signal is not heard.

(Embodiment 2) Next, a decoding apparatus according to Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 6 is a block diagram showing the functional arrangement of the decoding device 30a according to the second embodiment. This decoding device 30a separates only the narrow band bit stream S1 from the wide band bit stream S0 output from the coding device 10 and decodes it by a narrow band decoding unit 31.
A wideband decoding unit 32 that separates and decodes only the band expansion bitstream S2, a narrowband PCM signal (narrowband PCM signal) decoded by the narrowband decoding unit 31, and a wideband decoding unit. The selection unit 34 that selects one of the wideband PCM signal (wideband PCM signal) decoded by 32 and expanded by a narrow band.
And a mode setting unit 33a for setting the signal selection mode of the selection unit 34.

The narrow band decoding unit 31 includes a narrow band bit stream separation unit 311, a first narrow band conversion unit 312, and a second narrow band conversion unit 313. The wideband decoding unit 32 includes a band expansion bitstream separation unit 321.
And a first wideband conversion unit 322 and a second wideband conversion unit 32.
3 is included.

As shown in FIG. 5, the input coded signal (wide band bit stream S0) has a narrow band bit stream S1 obtained by coding a PCM signal and a reproduction band of this narrow band bit stream S1 to a high band. Band expansion bit stream S2 in which band expansion information for expansion is encoded
And are multiplexed for each frame.

The narrow band bit stream separation unit 311 of the narrow band decoding unit 31 extracts the narrow band bit stream S1 from the input coded signal (wide band bit stream S0).
Only separate.

The first narrow band converter 312 converts the narrow band bit stream S1 into an intermediate signal M1. The second narrow band conversion unit 313 converts the intermediate signal M1 into the PCM signal 1
Convert to.

The band expansion bitstream separation unit 321 of the wideband decoding unit 32 separates only the band expansion bitstream S2 from the input coded signal (wideband bitstream S0).

The first wide band conversion unit 322 uses the output of the band expansion bit stream separation unit 321 and the intermediate signal M1 output from the first narrow band conversion unit 312,
Convert to the intermediate signal M2.

The second wideband converter 323 converts the intermediate signal M2 into a PCM signal 2. Mode setting unit 33a
Can be set to at least a binary value of ON / OFF. When the set mode is ON, the selection unit 34 outputs the PCM signal 1 and the set mode is OFF.
In the case of, the PCM signal 2 is output.

Each unit constituting such a decoding device 30a provides a CPU, a ROM storing a program executed by the CPU, a work area at the time of executing the program, and the like as in the encoding device 10. It is realized by a memory or the like that temporarily stores the data and the like of the input coded signal.

The operation of the decoding device 30a thus configured will be described. First, the narrowband bitstream separation unit 311 of the narrowband decoding unit 31 acquires the input coded signal (wideband bitstream S0) and separates only the narrowband bitstream S1 from it. Here, the narrow band bit stream S1 is, for example, MPE.
It is like a G standard AAC bitstream. In this case, as a method of separating this from the input encoded signal, it may be separated according to the grammatical rule defined by the MPEG standard AAC method, and a widely known technique may be used (I
SO / IEC 13818-7: 1997. ).

Next, the band expansion bit stream separation unit 321 of the wide band decoding unit 32 acquires the wide band bit stream S0 which is the input coded signal, and separates only the band expansion bit stream S2 from it. Here, the band expansion bit stream S2 includes information (band expansion information S21) for expanding the reproduction band when the narrow band bit stream S1 is reproduced. The band expansion information S21 is, for example, information for controlling a process of moving a part of the frequency spectrum generated from the narrow band bit stream S1 to a high frequency region according to a predetermined rule.

Next, the first narrow band conversion section 312 converts the narrow band bit stream S1 into the intermediate signal M1.
Here, the intermediate signal M1 is, for example, a frequency spectrum signal which is a previous stage of the reproduced PCM signal. FIG. 7 shows an example thereof. A portion α surrounded by a solid line shown in FIG. 7 is a frequency band of the frequency spectrum signal generated by the first narrowband conversion unit 312. Alternatively, the intermediate signal M1 may be a time axis signal which is a stage before the PCM signal to be reproduced. For example, if the reproduced PCM signal is a signal represented by a 16-bit integer, the intermediate signal M1 may be a signal represented by a 32-bit floating point, or 3
It may be a signal represented by a 2-bit integer.

Next, the first wide band conversion unit 322 uses the output of the band expansion bit stream separation unit 321 to the wave number spectrum signal, that is, the information for expanding the reproduction band, and performs band expansion processing. To generate an intermediate signal M2. FIG. 8 shows an example thereof. A portion β surrounded by a dotted line in FIG. 8 is the first wideband conversion unit 322.
It is the frequency band of the frequency spectrum signal compensated by. Here, for example, a process of moving a part of the frequency spectrum generated from the narrow band bit stream to a high frequency region according to a predetermined rule is performed. Here, the intermediate signal M2 is, for example,
It may be a frequency spectrum signal which is the previous stage of the reproduced PCM signal, or P reproduced.
It may be a time axis signal which is a stage before the CM signal.
For example, if the reproduced PCM signal is a signal represented by a 16-bit integer, the intermediate signal M2 may be a signal represented by a 32-bit floating point, or a 32-bit integer. It may also be the signal represented.

Next, if the intermediate signal M1 is a frequency spectrum signal, the second narrow band conversion section 313 converts the frequency spectrum signal into a narrow band time axis signal by means of inverse MDCT processing, for example. Convert. Alternatively, if the intermediate signal M2 is a time-axis signal which is the previous stage of the PCM signal to be reproduced, for example, if the intermediate signal M2 is a signal represented by a 32-bit floating point. , A PC that reproduces the floating point signal
The M signal is converted into a signal represented by a 16-bit integer.

Next, the second wideband conversion section 323 converts the intermediate signal M2, that is, the frequency spectrum signal whose band has been expanded shown in FIG. 8, into a wideband PCM signal. The method is also a process, such as an inverse MDCT process, for converting a frequency spectrum signal into a time axis signal.

Finally, the mode setting unit 33a sets at least two values of ON / OFF, but when the set mode is ON, the selection unit 34 outputs the output of the second narrow band conversion unit 313. When the set mode is OFF, the second wideband conversion unit 32 outputs the narrowband PCM signal
The wideband PCM signal which is the output of 3 is output.

As described above, according to the decoding device 30a of the second embodiment, the narrowband bitstream separation unit 311 for separating the narrowband bitstream S1 from the coded signal (wideband bitstream S0), and the code A band expansion bit stream separation unit 321 that separates the band expansion bit stream S2 from the encoded signal and a first narrow band conversion unit 31 that converts the narrow band bit stream S1 into the intermediate signal M1.
2, a first wideband conversion unit 322 that converts the intermediate signal M1 into an intermediate signal M2 by using the output (bandwidth expansion information S21) of the band expansion bitstream separation unit 321 and the intermediate signal M1, and a narrow band of the intermediate signal M1. The second narrowband conversion unit 313 that converts the PCM signal P1 into a wideband PCM and the intermediate signal M2 into a wideband PCM.
A second wideband conversion unit 323 for converting into a signal P2 and a mode setting unit 33 capable of setting at least a binary value of ON / OFF.
When the set mode is ON, the narrow band PCM signal P1 is output, and when the set mode is OFF,
The output PCM signal P2 whose band is expanded by including the selection unit 34 which outputs the wide band PCM signal P2,
The output PCM signal P1 whose band has not been expanded can be easily switched and listened to.

(Embodiment 3) Next, a decoding apparatus 30b according to Embodiment 3 of the present invention will be described. Figure 9
FIG. 9 is a block diagram showing a functional configuration of a decoding device 30 according to a decoding device 30b according to the third embodiment of the present invention.
In addition, the same numbers are given to the portions corresponding to the decoding device 30a in FIG. 6, the description thereof will be omitted, and only different portions will be described in detail.

Now, in the decoding device 30a according to the second embodiment, the band-extended PCM signal P is used.
2 and the output PCM signal P1 whose band has not been expanded are configured to be selected by the selection unit 34. However, in this decoding device 30b, a PCM signal that is not expanded in band is further provided with the control unit 35. It is configured to reduce the amount of processing when outputting P1.

The control section 35 includes a mode setting section 33.
When the mode set in step 1 is OFF, at least a part of the means of at least one of the first wideband conversion unit 322 and the second wideband conversion unit 323 is stopped. For example, the processing of the second wideband conversion unit 323 is not performed.

As described above, this processing is, for example, processing for converting the frequency spectrum signal whose band has been expanded into the PCM signal P2. In practice, the frequency spectrum signal such as the inverse MDCT processing is used for the time axis. It is a process of converting into a signal. As a result, a very large amount of processing is required to execute this processing. Therefore, when the set mode is OFF, the bandwidth expanded PC
Since it is not necessary to output the M signal P2, this process can be stopped, and the amount of processing can be reduced or reduced.
This will contribute to the reduction of power consumption.

Of course, since the processing of the first wide band conversion section 322 is not necessary, it is desirable to stop this processing as well. When the processing of the first wideband conversion unit 322 is also stopped,
Furthermore, it will contribute to the reduction of power consumption.

(Embodiment 4) Next, a decoding apparatus 30c according to Embodiment 4 of the present invention will be described. Figure 1
0 is a block diagram showing a functional configuration of the decoding device 30c according to the third embodiment of the present invention. Note that parts corresponding to those of the decoding device 30b in FIG. 9 are assigned the same numbers, explanations thereof are omitted, and only different parts will be described in detail.

Now, in the decoding apparatus 30b according to the third embodiment, when the mode set by the mode setting unit 33 is OFF, the control unit 35 causes the first wideband conversion unit 322 and the second wideband conversion unit 322 to operate. Wideband converter 323
Was configured to stop the operation of at least some of the means in any of the above. On the other hand, decoding apparatus 30c according to Embodiment 4 of the present invention is configured to further reduce the amount of processing when outputting output PCM signal P1 whose band has not been expanded.

That is, in the decoding device 30c,
Furthermore, the output of the mode setting unit 33c is configured to be input to the band expansion bitstream separation unit 321. When the mode set by the mode setting unit 33c is OFF, the band expansion bitstream separation unit 321 of the decoding device 30c uses the band expansion bitstream S2 based on the information L indicating the length of the band expansion bitstream S2. Is separated from the input encoded signal. That is, since the information L indicating the length of the band expansion information S21 is multiplexed in the band expansion bit stream S2, this length information L
Based on the above, the reading of the band expansion information S21 included in the band expansion bit stream S2 is skipped.

Therefore, in the decoding device 30c, FIG.
As shown in FIG. 1, after processing the decoding of the narrow band bit stream S1 for each frame, the reading and decoding of the band expanding bit stream S2 (band expanding information S21) are skipped, and the narrow band of the next frame is processed. The processing of the bit stream S1 can be started, and the processing amount can be significantly reduced.

Specifically, as shown in FIG. 13, the mode setting unit 33c of the decoding device 30c causes the band expansion bit stream separation unit 321 to set the length of the band expansion information S21 included in the band expansion bit stream S2. The acquisition process of the information L is executed for each frame (S21).

Then, the mode setting section 33c determines for each frame whether the mode is the wideband mode or the compatible mode (S31). If the result of determination is that it is the wideband mode, the mode setting unit 33c outputs "OFF" (S32), operates the narrowband decoding unit 31 and the wideband decoding unit 32 (S33), and outputs the band expansion information S21. Used to output a broadband PCM signal. On the other hand, if the determination result is the narrow band mode, the mode setting unit 33c
"ON" is output (S34), the band expansion information S21 is acquired, and the first wideband conversion unit 322 and the second wideband conversion unit 32 are acquired.
The process of 3 is skipped, only the narrow band decoding unit 31 is operated (S35), and the narrow band PCM signal is output.

The determination process in step S31 is performed by the subroutine shown in FIG. In this mode determination routine, the mode setting unit 33c first
Whether the wide band mode or the narrow band mode is set is determined depending on whether the type or attribute of the source to be reproduced belongs to news, music, or the like (S311). If the source is required to reproduce up to a high frequency band such as music, the mode setting unit 33c selects a wide band mode and a narrow band mode depending on the state of the device, for example, whether the battery level of the mobile phone is low or high. It is determined which of the two is to be set (S312). When the remaining battery energy is high, the mode setting unit 33c further determines whether or not the user's setting is “OFF” for the selection unit 34 (S313). If "OFF", that is, 3
Only when the two conditions (S311 to S313) are met, the mode setting unit 33c sets the broadband mode (S314),
Return to the main routine. On the other hand, if any of the three conditions is not satisfied, the narrow band mode is set (S315), and the process returns to the main routine.

Therefore, wasteful processing can be significantly reduced, power consumption of the battery can be reduced, and long-term use can be ensured. In addition, the above-mentioned Embodiments 1 to 4
Although the encoding device 10 and the decoding devices 30a to 30a of the present invention have been realized by a program or the like, each unit may be realized by a logic circuit or the like and may be configured by LSI hardware.

Further, in the above-mentioned second to fourth embodiments, the band extension information S21 is supplemented by the frequency band to the information of the narrow band bit stream S1, but it may be supplemented on the time axis. Further, in the above-described embodiment, the case of applying to AAC has been described, but it goes without saying that the present invention can be applied to a system including an encoding device and a decoding device of another system such as MP3 Pro.

Further, application examples of the coding apparatus and the decoding apparatus shown in the above-mentioned first to fourth embodiments and a system using the same will be described here. FIG. 15 is a block diagram showing the overall configuration of a content supply system ex100 that realizes a content distribution service.

This contents supply system ex100 is
For example, the streaming server ex103, the internet service provider ex102, and the computer ex1
11, PDA (personal digital a
Internet ex101 that connects the streaming server ex103 and the Internet service provider ex102 with each device such as a mobile phone ex114, a mobile phone ex114, and a mobile phone ex115 with a camera.
And a telephone network ex104 and base stations ex107 to ex110, which connect the Internet service provider ex102 to the devices ex111, ex112, ex114, and ex115.

The content supply system ex100 is not limited to the combination as shown in FIG. 15, and any combination may be connected. Further, each device may be directly connected to the telephone network ex104 without going through the base stations ex107 to ex110 which are fixed wireless stations.

Also, the streaming server ex103 is
The encoding device described in the first embodiment is held, and the source of news or the like sent via the Internet service provider ex102 or the source of music or the like stored in advance is encoded by this encoding device. Device ex111, ex112, ex114, ex that issued the distribution request
This is a server for stream distribution to 115.

Each device ex111 constituting this system,
ex112, ex114, and ex115 are the same as those in the second embodiment.
The LSI ex117 that implements the encoding device and the decoding device described in 4 in hardware is held,
The source delivered in the stream is decoded by the decoding device and then reproduced. Here, mobile phones ex114, ex
115 is a PDC (Personal Digital)
Communications, CDMA (C
ode Division Multiple Acce
ss) system, W-CDMA (Wideband-Cod)
e Division Multiple Acces
s) system or GSM (Global System)
m for Mobile Communicatio
ns) mobile phone or PHS (Person)
al Handyphone System), etc.,
Either is fine. A mobile phone will be described as an example of the device.

FIG. 16 is a diagram showing an external configuration of a mobile phone ex115 using the encoding device and the decoding device described in the above embodiment. The mobile phone ex115 is a base station ex
Antenna ex20 for transmitting and receiving radio waves with 110
1. Images from a CCD camera, a camera unit ex203 capable of taking still images, images taken by the camera unit ex203,
A display unit ex202 such as a liquid crystal display for displaying data in which the image received by the antenna ex201 is decoded, a main unit including operation keys ex204 group, a sound output unit ex208 such as a speaker for outputting sound, a sound A voice input unit ex205 such as a microphone for inputting, captured video or still image data, received mail data,
A recording medium ex207 for storing encoded data or decoded data such as moving image data or still image data, and a recording medium in the mobile phone ex115.
It has a slot portion ex206 for mounting the ex207. The recording medium ex207 is an EEPROM (Electrica) that is a nonvolatile memory that can be electrically rewritten and erased in a plastic case such as an SD card.
lily Erasable and Programma
It stores a flash memory device which is a kind of ble read only memory).

Further, the mobile phone ex115 is shown in FIG.
This will be described using 7. The mobile phone ex115 has a display unit ex2
02 and an operation key ex204, a main control unit ex311 configured to integrally control each unit of the main body unit, a power supply circuit unit ex310, an operation input control unit ex304, an image encoding unit ex312, a camera interface unit. ex30
3. LCD (Liquid Crystal Disp)
control unit ex302, image decoding unit ex309, demultiplexing unit ex308, recording / reproducing unit ex307, modulation / demodulation circuit unit ex
The audio processing unit ex305 and 306 are connected to each other via a synchronous bus ex313.

The power supply circuit unit ex310 is in a state in which the digital portable telephone set with camera ex115 can be operated by supplying power from the battery pack to each unit when the call ends and the power key is turned on by the user's operation. To start.

The mobile phone ex115 is based on the control of the main control unit ex311 composed of a CPU, a ROM, a RAM, etc., and encodes the voice signal collected by the voice input unit ex205 in the voice call mode with the encoding device described in the present invention. The audio processing unit ex305 having a configuration including a decoding device converts the audio data into digital audio data, and the modulation / demodulation circuit unit ex306
Then, the transmission / reception circuit unit ex301 performs a digital-analog conversion process and a frequency conversion process, and then transmits the data via the antenna ex201. Also, the mobile phone ex115 amplifies the received signal received by the antenna ex201 in the voice call mode or the content receiving mode, performs frequency conversion processing and analog-digital conversion processing, and performs modulation / demodulation circuit section ex306 spectrum despreading processing and voice processing. After being converted into an analog audio signal by the unit ex305, this is output via the audio output unit ex208.

Further, when sending an electronic mail in the data communication mode, the text data of the electronic mail input by operating the operation keys ex204 of the main body is sent to the main control unit ex311 via the operation input control unit ex304. . The main control unit ex311 performs spread spectrum processing on the text data by the modulation / demodulation circuit unit ex306, and the transmission / reception circuit unit ex306.
After performing digital-analog conversion processing and frequency conversion processing at 301, the base station ex1 is transmitted via the antenna ex201.
Send to 10.

When transmitting image data in the data communication mode, the image data captured by the camera unit ex203 is transferred to the image encoding unit via the camera interface unit ex303.
supply to ex312. When the image data is not transmitted, the image data captured by the camera unit ex203 is used as the camera interface unit ex303 and the LCD control unit ex3.
It is also possible to display directly on the display unit ex202 via 02.

The image encoding unit ex312 includes a camera unit ex20.
The image data supplied from No. 3 is compressed and encoded by the encoding method used in the image encoding apparatus shown in the above-mentioned embodiment to be converted into encoded image data, which is sent to the demultiplexing unit ex308. At this time, at the same time, the mobile phone ex115 demultiplexes the voice collected by the voice input unit ex205 during the image pickup by the camera unit ex203 as digital voice data via the voice processing unit ex305.
Send to.

The demultiplexing unit ex308 is an image coding unit ex3.
Coded image data supplied from 12 and the audio processing unit ex3
05 is multiplexed with the voice data supplied from the communication unit 05 by a predetermined method, and the resulting multiplexed data is modulated / demodulated by the modulation / demodulation circuit unit ex3.
The spread spectrum processing is performed in 06, and the transmission / reception circuit unit ex301
Then, the digital-analog conversion process and the frequency conversion process are performed, and then the data is transmitted via the antenna ex201.

When receiving the data of the moving image file linked to the homepage or the like in the data communication mode, the modulation / demodulation circuit unit ex306 performs the spectrum despreading process on the received signal received from the base station ex110 via the antenna ex201, and the result is obtained. The obtained multiplexed data is demultiplexed by the demultiplexing unit ex3.
08.

To decode the multiplexed data received via the antenna ex201, the demultiplexing unit ex308
Separates the multiplexed data into a coded bit stream of image data and a coded bit stream of audio data, and supplies the coded image data to the image decoding unit ex309 via the synchronization bus ex313. The audio data is supplied to the audio processing unit ex305.

Next, the image decoding unit ex309 generates reproduced moving image data by decoding the encoded bit stream of the image data, and supplies this to the display unit ex202 via the LCD control unit ex302, Thereby, for example, the moving image data included in the moving image file linked to the home page is displayed. At this time, at the same time, the voice processing unit ex3
05 is, after converting the voice data into an analog voice signal,
This is supplied to the audio output unit ex208, whereby the audio data included in, for example, a moving image file linked to a home page is reproduced.

The system is not limited to the above example, and at least one of the encoding device and the decoding device according to the above-described embodiments can be incorporated in a satellite or terrestrial digital broadcasting system.

Further, the audio signal can be coded by the coding device shown in the above embodiment and recorded in the recording medium. Specific examples include a DVD recorder that records an audio signal on a DVD disc and a recorder such as a disc recorder that records on a hard disk. It can also be recorded on an SD card. If the recorder is equipped with the decoding device described in the above embodiment, the sound recorded on the DVD disk or the SD card can be reproduced and viewed.

There are three types of terminals such as the above-mentioned mobile phone ex114, that is, a transmission / reception terminal having both an encoder and a decoder, a transmission terminal having only an encoder and a reception terminal having only a decoder. The implementation format of is conceivable.

As described above, it is possible to use the coding apparatus or the decoding apparatus shown in the above-described embodiments in any of the above-mentioned devices / systems, and by doing so, the effects explained in the above-mentioned embodiments Can be obtained.

[0097]

As is apparent from the above description, the decoding apparatus according to the present invention is a band for expanding the reproduction band of the first bit stream obtained by encoding the digital sound signal and the digital signal of the sound. A decoding device for decoding a coded signal including a second bit stream obtained by coding extension information, wherein a digital signal of a first sound is generated based on the first bit stream included in the coded signal. First reproduction means for reproducing, and the first reproduction means included in the encoded signal.
A second reproducing means for reproducing a digital signal of a second sound having a wider band than that of the first sound reproduced by the first reproducing means based on the bit stream and the second bit stream; and the first reproducing means. It is characterized by further comprising: selecting means for selecting and outputting either the digital signal of the reproduced first sound or the digital signal of the second sound reproduced by the second reproducing means.

As a result, the digital signal of the wide band second sound output from the second reproducing means by the selecting means and the first
The narrow band first sound digital signal outputted from the reproducing means can be extremely easily selected and reproduced.

In this case, the decoding device further comprises mode setting means for notifying the selecting means of mode information designating either the first mode or the second mode,
When the mode information notified from the mode setting means indicates the first mode, the selecting means selects and outputs the digital signal of the first sound reproduced by the first reproducing means, and outputs the second mode. In the case of, the digital signal of the second sound reproduced by the second reproducing means may be selected and output.

As a result, the selection of the digital signal of the first sound in the narrow band and the digital signal of the second sound in the wide band is determined (designated) by the mode instructed by the user or the mode is determined by the type of the signal. It is possible to determine the mode depending on the state of the device.

Also, the first reproducing means converts the first bit stream separated from the encoded signal into the first bit stream and the first bit stream separated by the first separating means into an intermediate signal. A second conversion unit that converts the intermediate signal obtained by the conversion in the first conversion unit into a digital signal of the first sound;
The reproducing means has second separating means for separating the second bit stream from the encoded signal, and the band expansion information contained in the second bit stream separated by the second separating means and the first converting section. Is used to reproduce the digital signal of the second sound by using the intermediate signal obtained by the conversion of
The second reproducing means may further include information indicating a frequency spectrum, and the second reproducing means may further generate the frequency spectrum from the information of the frequency spectrum obtained by the first conversion unit according to the band expansion information. A wideband spectrum generation unit that generates a frequency spectrum in a band wider than the band, and a wideband sound that generates a digital signal of the wideband sound from the generated frequency spectrum and the frequency spectrum obtained by the first conversion unit. And a digital signal generating section, and the decoding device further notifies the selection means of mode information designating either the first mode or the second mode. When the mode information notified from the mode setting means indicates the first mode, the selecting means includes: 1 selects and outputs the digital signal of the reproduced sound reproduction means, to indicate a second mode,
A configuration may be adopted in which the digital signal of the sound reproduced by the second reproducing means is selected and output.

As a result, it becomes possible to efficiently reproduce a wide band using the intermediate signal and select the mode information. Further, in the decoding device according to the present invention, the mode setting means further notifies the mode information to the second reproducing means, and the second reproducing means has the mode notified from the mode setting means. When the information indicates the first mode, reproduction from the second bit stream to the digital signal of the second sound is stopped, or the mode setting means further includes the mode information. Notifying the second reproduction means, and the second reproduction means is at least one of generation of the frequency spectrum by the wideband spectrum generation unit and generation of a second sound digital signal by the second sound digital signal generation unit. May be stopped.

As a result, when the digital signal of the second sound is not reproduced, the unnecessary processing can be efficiently stopped, and the processing amount can be reduced and the power consumption can be reduced.

Further, the first bit stream and the second bit stream are alternately multiplexed for each predetermined frame, and the second reproducing means extracts the second bit stream from the encoded signal. The second bit stream is configured to have a second separating unit for separating, the code amount of the band expansion information is variable for each frame, and the second bit stream has size information indicating the size of the code amount. Are multiplexed, and the second separating means is
The second bitstream is separated from the encoded signal based on the size information included in the second bitstream, or the size information is arranged at the head of the second bitstream. The second demultiplexing unit specifies the size of the code amount of the band expansion information from the size information included at the head of the second bitstream, and based on the specified size, the second separation unit from the encoded signal. The bit stream is separated, or the size information is N bits indicating the size of the code amount of the band expansion information, or (N +
M) bits, and the second separation unit specifies the size of the code amount of the band expansion information from the N or (N + M) bits included at the beginning of the second bit stream,
The second bit stream is separated from the coded signal based on the specified size, or N bits in the (N + M) bits are N bits.
A bit may represent a maximum value that can be expressed, and the M bit may indicate a size of a code amount that exceeds the size indicated by the maximum value in the code amount of the band extension information.

As a result, efficient wide band and narrow band reproduction based on a small amount of bit size information can be performed, while the band can be expanded simply by looking at the size information when a high band signal is not reproduced. Since it can be played back while skipping the processing for reading information and wideband decoding,
It is possible to significantly reduce the amount of processing, and consequently, the power consumption.

Further, the coding apparatus of the present invention is a coding apparatus for coding a digital signal of sound, and a first coding means for coding the inputted digital signal of sound, and the input device. A second encoding unit that generates and encodes band expansion information for expanding the reproduction band of the signal encoded by the first encoding unit from the digital sound signal, and the second encoding unit. Size calculation means for calculating the size of the obtained coded signal; first multiplexing for multiplexing the information indicating the size calculated by the size calculation means and the coded signal obtained by the second coding means And a second multiplexing means for multiplexing the first bit stream obtained by the first encoding means and the second bit stream obtained by the first multiplexing means. And

As a result, it is possible to very easily realize the selection of the wide band sound digital signal and the narrow band sound digital signal in the decoding device, and it is unnecessary to reproduce the narrow band PCM signal. The skip of processing can be realized very easily.

Here, the second multiplexing means is the first multiplexing means.
The bit stream and the second bit stream are alternately multiplexed for each predetermined frame, or the first multiplexing means has information indicating the size of the second bit stream. The information indicating the size and the encoded signal are multiplexed so as to be arranged at the head, and the size information is N bits indicating the size of the code amount of the band expansion information. , Or (N + M) bits, and the size calculating means determines whether the size of the code amount of the band expansion information is less than the maximum value represented by N bits or not. It is characterized by deciding which of the bits to use, or N in the (N + M) bits.
The bit indicates the maximum value that N bits can represent, and the M
The bit may indicate the size of the code amount that exceeds the size indicated by the maximum value in the code amount of the band expansion information.

As a result, the decoding device can realize efficient wideband and narrowband reproduction based on the size information of a small bit amount, while the highband signal is not reproduced by simply looking at the size information. It is possible to replay while skipping the processing for reading the information for expanding the bandwidth and the processing for wideband decoding, thereby significantly reducing the processing amount, and thus, significantly reducing the power consumption.

Since such an effect is remarkably exhibited in a battery-operated device such as a mobile phone, the practicability of the present invention is extremely high. In addition, in a device that decodes encoded data that has been subjected to such a band expansion technique, in consideration of the power consumption of the device, the taste of the listener, and the like, is it possible to reproduce the band-expanded second sound digital signal? , Whether to reproduce the digital signal of the first sound that has not been band expanded,
It should be selectable, and for example, in the case of receiving a voice broadcast such as news, it is desired to reproduce the digital signal of the first sound whose band has not been expanded to reduce power consumption. This is also in full agreement with the present inventors' opinions.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of an encoding device according to a first embodiment.

FIG. 2 is a flowchart showing a flow of processing executed by each unit of the encoding device 10 shown in FIG.

FIG. 3 is a diagram showing details of processing executed when the code amount calculated in step S13 of FIG. 2 is multiplexed into the band extension bit stream S2.

FIG. 4 is a diagram showing an example of a configuration of length information L of a bitstream created by the processing shown in FIG.
In particular, FIG. 4A shows an N-bit bit field (si
It is a figure which shows the case where length information L is comprised only by ze_of_ext). FIG. 4B is a diagram showing a case where the length information L is composed of two N-bit bit fields (size_of_ext) and M-bit additional bit fields (size_of_esc).

5 is a diagram showing a format configuration of a bitstream output from the encoding device 10. FIG.

FIG. 6 is a block diagram showing a functional configuration of a decoding device according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a frequency band in the case of reproducing a narrow band.

FIG. 8 is a diagram showing frequency bands in the case of wideband reproduction.

FIG. 9 is a block diagram showing a functional configuration of a decoding device according to a third embodiment.

FIG. 10 is a block diagram showing a functional configuration of a decoding device according to a fourth embodiment.

FIG. 11 is a diagram showing a state of skipping separation of band extension information based on length information in the case of narrow band reproduction.

FIG. 12 is a flowchart showing a length information acquisition process.

FIG. 13 is a flowchart showing details of decoding processing.

FIG. 14 is a flowchart showing details of mode determination processing.

FIG. 15 is a block diagram showing an overall configuration of a content supply system.

FIG. 16 is a diagram showing an external configuration of a mobile phone.

FIG. 17 is a block diagram showing a circuit configuration of a mobile phone.

[Fig. 18] Fig. 18 is a diagram illustrating a frequency band encoded in the AAC standard.

FIG. 19 is a diagram showing a frequency band expanded by a band expansion process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Coding device 11 Narrowband coding part 12 Band expansion coding part 13 Code amount calculation part 14 Code amount multiplexing part 15 Stream multiplexing parts 30a, 30b, 30c Decoding device 31 Narrowband decoding part 32 Wideband decoding Parts 33a, 33b, 33c Mode setting unit 34 Selection unit 35 Control unit 311 Narrow band bit stream separation unit 312 First narrow band conversion unit 313 Second narrow band conversion unit 321 Band expansion bit stream separation unit 322 First wide band conversion unit 323 Second wide band conversion unit S0 Wide band bit stream S1 Narrow band bit stream S2 Band expanded bit stream S21 Band expanded information L Length information M1, M2 Intermediate signal P1, P2 PCM signal

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiaki Sawada             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D045 DA20                 5J064 AA00 AA02 BA00 BC02 BC18                       BC25 BC29 BD02

Claims (34)

[Claims] 1. A coded signal composed of a first bit stream obtained by encoding a sound digital signal and a second bit stream obtained by encoding band expansion information for expanding a reproduction band of the sound digital signal. A first decoding unit for reproducing a digital signal of a first sound based on the first bit stream included in the encoded signal; and the first decoding unit included in the encoded signal. A second band having a wider band than the digital signal of the first sound reproduced by the first reproducing means based on the bit stream and the second bit stream.
Second reproducing means for reproducing a digital sound signal, and selecting one of the digital signal of the first sound reproduced by the first reproducing means and the digital signal of the second sound reproduced by the second reproducing means. A decoding device, comprising: a selecting unit for outputting the output. 2. The decoding device further comprises mode setting means for notifying the selection means of mode information designating either the first mode or the second mode, and the selection means comprises the mode setting means. When the mode information notified from the first mode indicates the first mode, the digital signal of the first sound reproduced by the first reproduction means is selected and output, and when the second mode is indicated, the second mode is selected. 2. The decoding apparatus according to claim 1, wherein the digital signal of the second sound reproduced by the reproducing means is selected and output. 3. The mode setting means, based on an instruction from a user, generates mode information designating either the first mode or the second mode and notifies the selecting means of the mode information. The decoding device according to claim 2. 4. The mode setting means generates mode information designating one of the first mode and the second mode based on a type of a digital signal of a sound included in the first bitstream, and the mode setting means generates the mode information. The decoding device according to claim 2, wherein the decoding means is notified. 5. The mode setting means, when the type of the digital signal of the sound included in the first bit stream is music, generates the mode information designating the second mode and notifies the selecting means. 5. When the type of the digital signal of the sound included in the first bit stream is not music, the mode information designating the first mode is generated and notified to the selecting means. Decryption device. 6. The mode setting means generates mode information designating one of the first mode and the second mode according to the state of a device including the decoding device, and notifies the selecting means of the mode information. The decoding device according to claim 2, wherein 7. The mode setting means, when the remaining energy level of a battery provided in the device is below a certain value,
The mode information designating the first mode is generated and notified to the selecting means, and when the remaining energy of the battery of the device exceeds a certain value, the mode information designating the second mode is generated and the selection is made. 7. The decoding device according to claim 6, wherein the means is notified. 8. The mode setting means further notifies the second reproduction means of the mode information, and the second reproduction means is such that the mode information notified from the mode setting means indicates a first mode. The decoding apparatus according to claim 2, wherein the reproduction of the second bit stream from the second bit stream to the digital signal is stopped. 9. The first reproducing unit separates the first bit stream from the encoded signal, and converts the first bit stream separated by the first separating unit into an intermediate signal. A first conversion unit; and a second conversion unit that converts the intermediate signal obtained by the conversion in the first conversion unit into a digital signal of a first sound, the second reproduction unit includes the encoded signal. The second bit stream separated by the second bit stream, the band expansion information included in the second bit stream and the intermediate obtained by the conversion in the first conversion unit. The decoding device according to claim 1, wherein the digital signal of the second sound is reproduced using the signal. 10. The decoding device according to claim 9, wherein the intermediate signal is information indicating a frequency spectrum. 11. The second reproduction unit further generates a frequency spectrum of a band wider than the band of the frequency spectrum from the information of the frequency spectrum obtained by the first conversion unit according to the band expansion information. And a wideband spectrum digital generation section for generating a wideband spectrum digital signal from the generated frequency spectrum and the frequency spectrum obtained by the first conversion section. The decoding device according to claim 10. 12. The decoding device further comprises mode setting means for notifying the selection means of mode information designating either the first mode or the second mode, and the selection means comprises the mode setting means. If the mode information notified from the first reproduction mode indicates the first mode, the digital signal of the sound reproduced by the first reproduction means is selected and output, and if the second mode indicates the second mode, the second reproduction means. 12. The decoding apparatus according to claim 11, wherein the digital signal of the sound reproduced by is selected and output. 13. The mode setting means further notifies the second reproducing means of the mode information, and the second reproducing means generates the frequency spectrum by the wideband spectrum generating section and digitalizes the wideband sound. The decoding device according to claim 12, wherein at least one of the generation of the digital signal of the second sound by the signal generation unit is stopped. 14. The decoding device according to claim 9, wherein the intermediate signal is a time base signal. 15. The first bitstream and the second bitstream
The bit stream is alternately multiplexed for each predetermined frame, and the second reproducing means has a second separating means for separating the second bit stream from the encoded signal. Item 1. The decoding device according to item 1. 16. A code amount of the band expansion information is variable for each frame, and size information indicating a size of the code amount is multiplexed in the second bit stream, and the second demultiplexing unit. 16. The decoding apparatus according to claim 15, wherein the demultiplexer separates the second bitstream from the coded signal based on size information included in the second bitstream. 17. The size information is arranged at the head of the second bit stream, and the second separating means determines the size of the code amount of the band expansion information from the size information included at the head of the second bit stream. 17. The decoding device according to claim 16, wherein the second bit stream is separated from the encoded signal based on the specified size. 18. The size information is N bits or (N + M) bits indicating the size of the code amount of the band expansion information, and the second separating means is included at the head of the second bit stream. 18. The size of the code amount of the band extension information is specified from the N or (N + M) bits, and the second bit stream is separated from the encoded signal based on the specified size. Decryption device. 19. The N bits in the (N + M) bits indicate a maximum value that can be expressed by the N bits, and the M bits indicate a code amount exceeding the size indicated by the maximum value in the code amount of the band extension information. 19. The decoding device according to claim 18, wherein the decoding device indicates the size of 20. An encoding device for encoding a sound digital signal, wherein the encoding device encodes an inputted sound digital signal.
Encoding means, and second encoding means for generating and encoding band expansion information for expanding the reproduction band of the signal encoded by the first encoding means from the input digital signal of sound. A size calculation means for calculating the size of the coded signal obtained by the second coding means, information indicating the size calculated by the size calculation means, and a coded signal obtained by the second coding means And a second multiplexing means for multiplexing the first bit stream obtained by the first encoding means and the second bit stream obtained by the first multiplexing means. And an encoding device. 21. The second multiplexing means alternately multiplexes the first bitstream and the second bitstream for each predetermined frame.
0 coding apparatus. 22. The first multiplexing means multiplexes the information indicating the size and the coded signal so that the information indicating the size is arranged at the head of the second bit stream. 22. The encoding device according to claim 21, wherein the encoding device is characterized in that: 23. The information indicating the size is N bits indicating the size of the code amount of the band expansion information, or (N +
M) bits, and the size calculation means determines whether N bits or (N + M) bits based on whether the size of the code amount of the band expansion information is less than the maximum value represented by N bits. 23. The encoding device according to claim 22, wherein it is determined whether to use. 24. The N bits in the (N + M) bits represent a maximum value that can be represented by the N bits, and the M bits represent a code amount of the band expansion information that exceeds a size indicated by the maximum value. 24. The encoding device according to claim 23, wherein 25. A communication system comprising an encoding device and a decoding device connected by a transmission line, wherein the encoding device encodes a digital signal of an input sound.
Encoding means, and second encoding means for generating and encoding band expansion information for expanding the reproduction band of the signal encoded by the first encoding means from the input digital signal of sound. A size calculation means for calculating the size of the coded signal obtained by the second coding means, information indicating the size calculated by the size calculation means, and a coded signal obtained by the second coding means And a second multiplexing means for multiplexing the first bit stream obtained by the first encoding means and the second bit stream obtained by the first multiplexing means. Means for reproducing the digital signal of the first sound based on the first bit stream included in the encoded signal, and the decoding device including the first reproducing means for reproducing the digital signal of the first sound. 1st bit stream A second band having a wider band than that of the digital signal of the first sound reproduced by the first reproducing means, based on the first and second bit streams
Second reproducing means for reproducing a digital sound signal, and selecting one of the digital signal of the first sound reproduced by the first reproducing means and the digital signal of the second sound reproduced by the second reproducing means. A communication system comprising: 26. Decoding an encoded signal composed of a first bit stream encoded with a sound digital signal and a second bit stream encoded with band expansion information for expanding the reproduction band of the sound digital signal. A first reproducing step of reproducing a digital signal of a first sound based on the first bit stream included in the encoded signal; and the first included in the encoded signal. A second band having a wider band than the digital signal of the first sound reproduced by the first reproducing means based on the bit stream and the second bit stream.
A second reproduction step for reproducing a digital sound signal, and selecting one of the first sound digital signal reproduced in the first reproduction step and the second sound digital signal reproduced in the second reproduction step. And a selection step of outputting the decoded data. 27. An encoding method for encoding a sound digital signal, comprising: encoding a inputted sound digital signal;
An encoding step; and a second encoding step for generating and encoding band expansion information for expanding the reproduction band of the signal encoded by the first encoding step from the input digital signal of sound. A size calculation step for calculating the size of the coded signal obtained in the second coding step, information indicating the size calculated in the size calculation step, and a coded signal obtained in the second coding step And a second multiplexing step of multiplexing the first bitstream obtained in the first encoding step and the second bitstream obtained in the first multiplexing step. An encoding method comprising the steps of: 28. A communication method in a system consisting of an encoding device and a decoding device connected by a transmission line, wherein the encoding device encodes a digital signal of an input sound.
An encoding step; and a second encoding step for generating and encoding band expansion information for expanding the reproduction band of the signal encoded by the first encoding step from the input digital signal of sound. A size calculation step for calculating the size of the coded signal obtained in the second coding step, information indicating the size calculated in the size calculation step, and a coded signal obtained in the second coding step And a second multiplexing step of multiplexing the first bitstream obtained in the first encoding step and the second bitstream obtained in the first multiplexing step. And a first reproduction step for reproducing a digital signal of a first sound based on the first bitstream included in the encoded signal, in the decoding device. And reproducing a digital signal of a second sound having a wider band than the digital signal of the first sound reproduced by the first reproducing step, based on the first bit stream and the second bit stream included in the encoded signal. And a selection step of selecting and outputting either the digital signal of the first sound reproduced in the first reproduction step or the digital signal of the second sound reproduced in the second reproduction step. A communication method comprising: 29. A coded signal composed of a first bit stream obtained by encoding a sound digital signal and a second bit stream obtained by encoding band expansion information for expanding a reproduction band of the sound digital signal are decoded. A first reproduction step of reproducing a digital signal of a first sound based on the first bit stream included in the encoded signal, and the first included in the encoded signal. A second band having a wider band than the digital signal of the first sound reproduced by the first reproducing means based on the bit stream and the second bit stream.
A second reproduction step for reproducing a digital sound signal, and selecting one of the first sound digital signal reproduced in the first reproduction step and the second sound digital signal reproduced in the second reproduction step. And a selection step of outputting the output as a program. 30. A program for encoding a sound digital signal, wherein the program encodes an inputted sound digital signal.
An encoding step; and a second encoding step for generating and encoding band expansion information for expanding the reproduction band of the signal encoded by the first encoding step from the input digital signal of sound. A size calculation step for calculating the size of the coded signal obtained in the second coding step, information indicating the size calculated in the size calculation step, and a coded signal obtained in the second coding step And a second multiplexing step of multiplexing the first bitstream obtained in the first encoding step and the second bitstream obtained in the first multiplexing step. A program comprising steps and. 31. A recording medium storing a coded signal decoded by a decoding device, wherein the decoding device generates a first sound based on a first bitstream included in the coded signal. A first reproduction means for reproducing a digital signal, and a wider band than the digital signal of the first sound reproduced by the first reproduction means on the basis of the first bit stream and the second bit stream included in the encoded signal. Second
Second reproducing means for reproducing a digital sound signal, and selecting one of the digital signal of the first sound reproduced by the first reproducing means and the digital signal of the second sound reproduced by the second reproducing means. The second reproduction means includes second separation means for separating the second bit stream from the encoded signal based on size information included in the second bit stream. The encoded signal stored in the recording medium includes a first bit stream obtained by encoding a sound digital signal and a second bit encoded by band expansion information for expanding a reproduction band of the sound digital signal. A stream, wherein the first bit stream and the second bit stream are multiplexed in block units each having a predetermined number of frames, The code amount of the area expansion information is variable for each frame, and each block storing the second bit stream has information indicating the end position of the block at the beginning of the block. Medium. 32. The recording medium according to claim 31, wherein the information indicating the end position of each block of the second bit stream is size information of the block. 33. The size information is N bits or (N + M) bits indicating a code amount size of the band expansion information, and the code amount size of the band expansion information is represented by N bits. 33. The recording medium according to claim 32, wherein which of N bits and (N + M) bits is used is determined based on whether the value is less than the maximum value. 34. N bits in the (N + M) bits represent a maximum value that can be represented by N bits, and the M bits represent a code amount of the band expansion information that exceeds a size indicated by the maximum value. 34. The recording medium according to claim 33, wherein