JP6872056B2 - Audio decoding device and audio decoding method - Google Patents

Description

The present invention relates to an audio decoding device and an audio decoding method.

A voice coding technology that compresses the amount of data of a voice signal and an acoustic signal to one tenth is an extremely important technology in signal transmission and storage. An example of a widely used voice coding technique is a transform coding method that encodes a signal in the frequency domain.

In transform coding, adaptive bit allocation, which allocates the bits required for coding for each frequency band according to an input signal, is widely used in order to obtain high quality at a low bit rate. The bit allocation method that minimizes distortion due to coding is allocation according to the signal power of each frequency band, and bit allocation is also performed in a form that takes human hearing into consideration.

On the other hand, there is a technique for improving the quality of the frequency band in which the number of allocated bits is very small. Patent Document 1 discloses a method of approximating the conversion coefficient of a frequency band in which the number of bits allocated is smaller than a predetermined threshold value by the conversion coefficient of another frequency band. Further, in Patent Document 2, a method of generating a pseudo-noise signal for a component that has been quantized to zero due to low power in the frequency band, and a component that has not been quantized to zero in another frequency band. A method of replicating the signal of is disclosed.

Furthermore, considering that the power of audio signals and acoustic signals is generally biased to the low frequency band rather than the high frequency band and has a large effect on the subjective quality, the high frequency band of the input signal is the encoded low frequency. Bandwidth expansion technology that uses bands to generate is also widely used. Bandwidth expansion technology can generate a high frequency band with a small number of bits, so it is possible to obtain high quality at a low bit rate. In Patent Document 3, after copying the spectrum of the low frequency band to the high frequency band, the spectrum shape is adjusted based on the information regarding the properties of the high frequency band spectrum transmitted from the encoder to generate the high frequency band. Is disclosed.

Japanese Unexamined Patent Publication No. 9-153811 U.S. Pat. No. 7447631 Patent No. 5203077

In the above technique, a component of the frequency band encoded with a small number of bits is generated so as to resemble the component of the original sound in the frequency domain. On the other hand, distortion becomes noticeable in the time domain, and the quality may deteriorate.

In view of the above problems, the present invention provides a voice decoding device and a voice decoding method capable of reducing distortion in the time domain of a component of a frequency band encoded with a small number of bits and improving quality. The purpose.

The voice decoding device of the present invention is a voice decoding device that decodes a coded voice signal and outputs a voice signal, and obtains a decoded signal by decoding a coding sequence including the coded voice signal. The decoding unit includes a decoding unit and a selective time-wrapping shaping unit that shapes the time-wrapping of the frequency band in the decoding signal based on the decoding-related information regarding the decoding of the coded sequence, and the decoding unit includes a part of the frequency band. In, a decoded signal is obtained by duplicating a signal in a frequency band different from the frequency band, and the selective time-wrapping shaping unit replaces the decoded signal corresponding to the frequency band in which the time-wrapping is not shaped with another signal in the frequency domain. ..

According to the present invention, it is possible to shape the time envelope of the decoded signal in the frequency band encoded with a small number of bits into a desired time envelope and improve the quality.

, Is a diagram showing the configuration of the audio decoding device 10 according to the first embodiment. It is a flowchart which shows the operation of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a figure which shows the structure of the 1st example of the decoding part 10a of the audio decoding apparatus 10 which concerns on 1st Embodiment. , Is a flowchart showing the operation of the first example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment. It is a figure which shows the structure of the 2nd example of the decoding part 10a of the audio decoding apparatus 10 which concerns on 1st Embodiment. It is a flowchart which shows the operation of the 2nd example of the decoding part 10a of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a figure which shows the structure of the 1st decoding part of the 2nd example of the decoding part 10a of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a flowchart which shows the operation of the 1st decoding part of the 2nd example of the decoding part 10a of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a figure which shows the structure of the 2nd decoding part of the 2nd example of the decoding part 10a of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a flowchart which shows the operation of the 2nd decoding part of the 2nd example of the decoding part 10a of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a figure which shows the structure of the 1st example of the selective time envelope shaping part 10b of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is a flowchart which shows the operation of the 1st example of the selective time envelope shaping part 10b of the voice decoding apparatus 10 which concerns on 1st Embodiment. It is explanatory drawing which shows the time envelope shaping process. It is a figure which shows the structure of the voice decoding apparatus 11 which concerns on 2nd Embodiment. It is a flowchart which shows the operation of the voice decoding apparatus 11 which concerns on 2nd Embodiment. It is a figure which shows the structure of the voice coding apparatus 21 which concerns on 2nd Embodiment. It is a flowchart which shows the operation of the voice coding apparatus 21 which concerns on 2nd Embodiment. It is a figure which shows the structure of the voice decoding apparatus 12 which concerns on 3rd Embodiment. It is a flowchart which shows the operation of the voice decoding apparatus 12 which concerns on 3rd Embodiment. It is a figure which shows the structure of the voice decoding apparatus 13 which concerns on 4th Embodiment. It is a flowchart which shows the operation of the voice decoding apparatus 13 which concerns on 4th Embodiment. It is a figure which shows the hardware configuration of the computer which functions as the voice decoding apparatus or voice coding apparatus of this embodiment. It is a figure which shows the program structure for functioning as a voice decoding apparatus. It is a figure which shows the program structure for functioning as a voice coding apparatus.

An embodiment of the present invention will be described with reference to the accompanying drawings. When possible, the same parts are designated by the same reference numerals and duplicate description is omitted.
[First Embodiment]
FIG. 1 is a diagram showing a configuration of an audio decoding device 10 according to the first embodiment. The communication device of the voice decoding device 10 receives the coding sequence in which the voice signal is encoded, and further outputs the decoded voice signal to the outside. As shown in FIG. 1, the voice decoding device 10 functionally includes a decoding unit 10a and a selective time envelope shaping unit 10b.

FIG. 2 is a flowchart showing the operation of the voice decoding device 10 according to the first embodiment.

The decoding unit 10a decodes the coded sequence and generates a decoded signal (step S10-1).

The selective time envelope shaping unit 10b receives the decoding-related information and the decoding signal, which are information obtained when decoding the coded sequence from the decoding unit, and selectively selects the time envelope of the component of the decoding signal as desired. (Step S10-2). In the following description, the time envelope of a signal represents a variation in the energy or power (and parameters equivalent thereto) of the signal in the time direction.

FIG. 3 is a diagram showing the configuration of a first example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment. As shown in FIG. 3, the decoding unit 10a functionally includes a decoding / dequantization unit 10aA, a decoding-related information output unit 10aB, and a time-frequency inverse conversion unit 10aC.

FIG. 4 is a flowchart showing the operation of the first example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment.

The decoding / dequantization unit 10aA performs at least one of decoding and dequantization on the coding series according to the coding method of the coding series to generate a frequency domain decoding signal (step S10). -1-1).

The decoding-related information output unit 10aB receives the decoding-related information obtained when the decoding / dequantization unit 10aA generates the decoding signal, and outputs the decoding-related information (step S10-1-2). Further, the decoding-related information may be output by receiving and analyzing the coded sequence to obtain the decoding-related information. The decoding-related information may be, for example, the number of coding bits for each frequency band, or information equivalent to this (for example, the average number of coding bits per frequency component for each frequency band). Furthermore, the number of coding bits for each frequency component may be used. Furthermore, the quantization step size for each frequency band may be used. Furthermore, it may be a quantized value of a frequency component. Here, the frequency component is, for example, a conversion coefficient for a predetermined time-frequency conversion. Furthermore, it may be energy or power for each frequency band. Furthermore, it may be information that presents a predetermined frequency band (which may be a frequency component). Further, for example, when the decoding signal generation includes processing related to other time envelope shaping, the information may be information related to the time envelope shaping process. For example, whether or not to perform the time envelope shaping process. It may be at least one of information, information on the time envelope shaped by the time envelope shaping process, and information on the strength of the time envelope shaping of the time envelope shaping process. At least one of the above examples is output as decoding-related information.

The time-frequency inverse conversion unit 10aC converts the frequency-domain decoding signal into a time-domain decoding signal by a predetermined time-frequency inverse conversion and outputs the signal (step S10-1-3). However, the frequency domain decoding signal may be output without reverse time-frequency conversion. For example, the case where the selective time envelope shaping unit 10b requests a signal in the frequency domain as an input signal is applicable.

FIG. 5 is a diagram showing a configuration of a second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment. As shown in FIG. 5, the decoding unit 10a functionally includes a coding sequence analysis unit 10aD, a first decoding unit 10aE, and a second decoding unit 10aF.

FIG. 6 is a flowchart showing the operation of the second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment.

The coded sequence analysis unit 10aD analyzes the coded sequence and separates it into a first coded sequence and a second coded sequence (step S10-1-4).

The first decoding unit 10aE decodes the first coding sequence by the first decoding method to generate the first decoding signal, and outputs the first decoding-related information which is the information related to the decoding (step S10-1). -5).

The second decoding unit 10aF uses the first decoding signal to decode the second coding sequence by the second decoding method to generate a decoding signal, and obtains the second decoding-related information which is the information related to the decoding. Output (step S10-1-6). In this example, the combination of the first decoding-related information and the second decoding-related information is the decoding-related information.

FIG. 7 is a diagram showing a configuration of a first decoding unit of a second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment. As shown in FIG. 7, the first decoding unit 10aE functionally includes a first decoding / dequantization unit 10aE-a and a first decoding-related information output unit 10aE-b.

FIG. 8 is a flowchart showing the operation of the first decoding unit of the second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment.

The first decoding / dequantization unit 10aE-a performs at least one of decoding and dequantization on the first coding series according to the coding method of the first coding series, and first. A decoded signal is generated and output (step S10-1-5-1).

The first decoding-related information output unit 10aE-b receives the first decoding-related information obtained when the first decoding / inverse quantization unit 10aE-a generates the first decoding signal, and receives the first decoding-related information. Is output (step S10-1-5-2). Further, the first coding-related information may be output by receiving and analyzing the first coding sequence to obtain the first decoding-related information. The example of the first decoding-related information may be the same as the example of the decoding-related information output by the decoding-related information output unit 10aB. Furthermore, the fact that the decoding method of the first decoding unit is the first decoding method may be used as the first decoding-related information. Further, the information indicating the frequency band (which may be a frequency component) included in the first decoding signal (the frequency band (which may be a frequency component) of the audio signal encoded in the first coding series) is related to the first decoding. It may be used as information.

FIG. 9 is a diagram showing a configuration of a second decoding unit of a second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment. As shown in FIG. 9, the second decoding unit 10aF functionally includes a second decoding / inverse quantization unit 10aF-a, a second decoding-related information output unit 10aF-b, and a decoding signal synthesis unit 10aF-c. Be prepared.

FIG. 10 is a flowchart showing the operation of the second decoding unit of the second example of the decoding unit 10a of the audio decoding device 10 according to the first embodiment.

The second decoding / dequantization unit 10aF-1 performs at least one of decoding and dequantization on the second coding series according to the coding method of the second coding series to perform the second decoding. A signal is generated and output (step s10-1-6-1). When generating the second decoded signal, the first decoded signal may be used. The decoding method (second decoding method) of the second decoding unit may be a band expansion method or a band expansion method using the first decoding signal. Further, as shown in Patent Document 1 (Japanese Unexamined Patent Publication No. 9-153811), the conversion coefficient of the frequency band in which the number of bits allocated by the first coding method is less than a predetermined threshold value is determined. As the coding method of 2, a decoding method corresponding to a coding method that approximates with a conversion coefficient of another frequency band may be used. Further, as shown in Patent Document 2 (US Pat. No. 7,447,631), the frequency component quantized to zero by the first coding method is simulated by the second coding method. A decoding method corresponding to a coding method that generates a noise signal or duplicates a signal of another frequency component may be used. Further, a decoding method corresponding to a coding method that approximates the component of the frequency by using a signal of another frequency component in the second coding method may be used. Further, the frequency component quantized to zero by the first coding method can be interpreted as the frequency component not encoded by the first coding method. In these cases, the decoding method corresponding to the first coding method is the first decoding method which is the decoding method of the first decoding unit, and the decoding method corresponding to the second coding method is the decoding method of the second decoding unit. It may be a certain second decoding method.

The second decoding-related information output unit 10aF-b receives the second decoding-related information obtained when the second decoding / inverse quantization unit 10aF-a generates the second decoding signal, and receives the second decoding-related information. Is output (step S10-1-6-2). Further, the second decoding-related information may be output by receiving and analyzing the second coding sequence to obtain the second decoding-related information. The example of the second decoding-related information may be the same as the example of the decoding-related information output by the decoding-related information output unit 10aB.

Further, the information indicating that the decoding method of the second decoding unit is the second decoding method may be used as the second decoding-related information. For example, information indicating that the second decoding method is a band expansion method may be used as the second decoding-related information. Further, for example, the information indicating the band expansion method for each frequency band of the second decoding signal generated by the band expansion method may be used as the second decoding information. Information indicating the band expansion method for each frequency band includes, for example, a sine signal that duplicates a signal from another frequency band, approximates a signal of the frequency band with a signal of another frequency band, and generates a pseudo noise signal. It may be information such as adding. Further, for example, when approximating a signal of the frequency with a signal of another frequency band, information on an approximation method may be used. Further, for example, when whitening is used when approximating a signal of the frequency with a signal of another frequency band, information on the intensity of whitening may be used as the second decoding information. Further, for example, when a pseudo noise signal is added when approximating a signal of the frequency with a signal of another frequency band, information regarding the level of the pseudo noise signal may be used as the second decoding information. Further, for example, when a pseudo noise signal is generated, information regarding the level of the pseudo noise signal may be used as the second decoding information.

Further, for example, in the second decoding method, the conversion coefficient of the frequency band in which the number of bits allocated by the first coding method is less than a predetermined threshold is approximated by the conversion coefficient of another frequency band, and pseudo. The information indicating that the decoding method corresponds to the coding method in which the conversion coefficient of the noise signal is added (may be replaced) or both may be used as the second decoding-related information. For example, information on the method of approximating the conversion coefficient of the frequency band may be used as the second decoding-related information. For example, when a method of whitening the conversion coefficient of another frequency band is used as the approximation method, the information on the intensity of whitening may be used as the second decoding information. For example, the information regarding the level of the pseudo noise signal may be used as the second decoding information.

Further, for example, the second coding method is a pseudo-noise signal for a frequency component quantized to zero by the first coding method (that is, not encoded by the first coding method). The information indicating that the coding method is used to generate a signal or duplicate a signal of another frequency component may be used as the second decoding-related information. For example, information indicating whether or not each frequency component is a component of a frequency quantized to zero by the first coding method (that is, not encoded by the first coding method) can be obtained. 2 Decoding-related information may be used. For example, information indicating whether to generate a pseudo noise signal for the frequency component or duplicate a signal of another frequency component may be used as the second decoding-related information. Further, for example, when duplicating a signal of another frequency component with respect to the frequency component, the information regarding the duplication method may be used as the second decoding-related information. The information regarding the duplication method may be, for example, the frequency of the duplication source. Further, for example, it may be information on whether or not to add a process to the frequency component of the copy source at the time of duplication, and further, information on the process to be added. Further, for example, when the process applied to the frequency component of the duplication source is whitening, it may be information on the intensity of whitening. Further, for example, when the processing applied to the frequency component of the duplication source is the addition of a pseudo noise signal, the information may be information on the level of the pseudo noise signal.

The decoding signal synthesis unit 10aF-c synthesizes and outputs a decoding signal from the first decoding signal and the second decoding signal (step S10-1-6-3). When the second coding method is a band extension method, generally, the first decoded signal is a low frequency band signal, the second decoded signal is a high frequency band signal, and the decoded signal is both of these. It will have a frequency band.

FIG. 11 is a diagram showing a configuration of a first example of the selective time envelope shaping unit 10b of the voice decoding apparatus 10 according to the first embodiment. As shown in FIG. 11, the selective time envelope shaping unit 10b functionally includes a time frequency conversion unit 10bA, a frequency selection unit 10bB, a frequency selective time envelope shaping unit 10bC, and a time frequency inverse conversion unit 10bD.

FIG. 12 is a flowchart showing the operation of the first example of the selective time envelope shaping unit 10b of the voice decoding device 10 according to the first embodiment.

The time-frequency conversion unit 10bA converts the time-domain decoding signal into a frequency-domain decoding signal by a predetermined time-frequency conversion (step S10-2-1). However, when the decoded signal is a signal in the frequency domain, the time-frequency conversion unit 10bA and the processing step S10-2-1 can be omitted.

The frequency selection unit 10bB uses at least one of the decoding signal in the frequency domain and the decoding-related information to select the frequency band in which the time-wrapping shaping process is performed on the decoding signal in the frequency domain (step S10-2-2). In the frequency selection process, a frequency component to be subjected to the time envelope shaping process may be selected. The selected frequency band (which may be a frequency component) may be a part of the frequency band (may be a frequency component) of the decoded signal, or may be the entire frequency band (which may be a frequency component) of the decoded signal.

For example, when the decoding-related information is the number of coding bits for each frequency band, a frequency band in which the number of coding bits is smaller than a predetermined threshold may be selected as the frequency band for performing the time wrapping shaping process. Similarly, in the case of information equivalent to the number of encoded bits for each frequency band, it is clear that the frequency band to be subjected to the time envelope shaping process can be selected by comparing with a predetermined threshold value. Further, for example, when the decoding-related information is the number of coding bits for each frequency component, a frequency component whose number of coding bits is smaller than a predetermined threshold may be selected as the frequency component to be subjected to the time envelope shaping process. .. For example, a frequency component whose conversion coefficient is not encoded may be selected as the frequency component to be subjected to the time envelope shaping process. Further, for example, when the decoding-related information is the quantization step size for each frequency band, a frequency band in which the quantization step size is larger than a predetermined threshold may be selected as the frequency band to be subjected to the time wrapping shaping process. Further, for example, when the decoding-related information is the quantization value of the frequency component, the frequency band to be subjected to the time envelope shaping process may be selected by comparing the quantization value with a predetermined threshold value. For example, a component having a quantization conversion coefficient smaller than a predetermined threshold value may be selected as a frequency component to be subjected to the time envelope shaping process. Further, for example, when the decoding-related information is energy or power for each frequency band, the frequency band to be subjected to the time envelope shaping process may be selected by comparing the energy or power with a predetermined threshold value. For example, when the energy or power of the frequency band subject to the selective time envelope shaping process is smaller than a predetermined threshold value, the time envelope shaping process may not be performed on the frequency band.

Further, for example, when the decoding-related information is information related to another time envelope shaping process, the frequency band in which the time envelope shaping process is not performed may be selected as the frequency band in which the time envelope shaping process is performed in the present invention.

Further, for example, when the decoding unit 10a has the configuration described in the second example of the decoding unit 10a and the decoding-related information is the coding method of the second decoding unit, it depends on the coding method of the second decoding unit. The frequency band decoded by the second decoding unit may be selected as the frequency band to be subjected to the time envelope shaping process. For example, when the coding format of the second decoding unit is the band expansion method, the frequency band decoded by the second decoding unit may be selected as the frequency band to be subjected to the time envelope shaping process. For example, when the coding format of the second decoding unit is the band expansion method in the time domain, the frequency band decoded by the second decoding unit may be selected as the frequency band to be subjected to the time envelope shaping process. For example, when the coding format of the second decoding unit is the band expansion method in the frequency domain, the frequency band decoded by the second decoding unit may be selected as the frequency band to be subjected to the time wrapping shaping process. For example, a frequency band in which a signal is duplicated from another frequency band by the band expansion method may be selected as the frequency band to be subjected to the time wrapping shaping process. For example, a frequency band obtained by approximating a signal of the frequency band using a signal of another frequency band in the band expansion method may be selected as the frequency band to be subjected to the time wrapping shaping process. For example, the frequency band in which the pseudo-noise signal is generated by the band expansion method may be selected as the frequency band to which the time envelope shaping process is performed. For example, a frequency band excluding the frequency band to which the sine signal is added by the band expansion method may be selected as the frequency band to which the time wrapping shaping process is performed.

Further, for example, the decoding unit 10a has the configuration described in the second example of the decoding unit 10a, and the number of bits allocated by the second coding method in the first coding method is less than a predetermined threshold. The conversion coefficient of the frequency band or component (which may be a frequency band or component not encoded by the first coding method) is approximated using the conversion coefficient of another frequency band or component, and the pseudo-noise signal. In the case of a coding method in which the conversion coefficient is added (or may be replaced), or both, the frequency band or component obtained by approximating the conversion coefficient using the conversion coefficient of another frequency band or component is used for time. It may be selected as a frequency band or component to be subjected to the wrapping shaping process. For example, a frequency band or component to which a conversion coefficient of the pseudo-noise signal is added (may be replaced) may be selected as the frequency band or component to be subjected to the time envelope shaping process. For example, the conversion coefficient may be selected as the frequency band or component to be subjected to the time envelope shaping process depending on the approximation method when approximating the conversion coefficient using the conversion coefficient of another frequency band or component. For example, when a method of whitening the conversion coefficient of another frequency band or component is used as the approximation method, the frequency band or component to be subjected to the time envelope shaping process may be selected according to the intensity of whitening. .. For example, when adding (or replacing) the conversion coefficient of the pseudo-noise signal, the frequency band or component to be subjected to the time envelope shaping process may be selected according to the level of the pseudo-noise signal.

Further, for example, the decoding unit 10a has the configuration described in the second example of the decoding unit 10a, and the second coding method is quantized to zero by the first coding method (that is, the first coding method). A coding method that generates a pseudo-noise signal or duplicates a signal of another frequency component (may be an approximation using a signal of another frequency component) for a frequency component (not encoded by the coding method of). In this case, the frequency component that generated the pseudo-noise signal may be selected as the frequency component to be subjected to the time-wrapping shaping process. For example, a frequency component obtained by duplicating a signal of another frequency component (which may be approximated by using a signal of another frequency component) may be selected as the frequency component to be subjected to the time envelope shaping process. For example, when duplicating a signal of another frequency component with respect to the frequency component (may be approximated by using a signal of another frequency component), a time wrapping shaping process is performed according to the frequency of the duplication source (approximate source). The frequency component to be applied may be selected. For example, the frequency component to be subjected to the time envelope shaping process may be selected depending on whether or not the process is applied to the frequency component of the copy source at the time of duplication. For example, the frequency component to be subjected to the time envelope shaping process may be selected according to the process to be applied to the frequency component of the copy source (approximate source) at the time of duplication (approximate). For example, when the process applied to the frequency component of the duplication source (approximate source) is whitening, the frequency component to be subjected to the time envelope shaping process may be selected according to the intensity of whitening. For example, a frequency component to be subjected to the time envelope shaping process may be selected according to the approximation method at the time of approximation.

The frequency component or frequency band selection method may be a combination of the above examples. Further, at least one of the decoding signal in the frequency domain and the decoding-related information may be used to select the frequency component or band to be subjected to the time-wrapping shaping process in the decoding signal in the frequency domain. Is not limited to the above example.

The frequency selective time envelope shaping unit 10bC shapes the time envelope of the frequency band selected by the frequency selection unit 10bB of the decoded signal into a desired time envelope (step S10-2-3). The time envelope shaping may be performed in units of frequency components.

The time envelope shaping method is, for example, a method of flattening the time envelope by filtering the conversion coefficient of the selected frequency band with a linear prediction inverse filter using the linear prediction coefficient obtained by linear prediction analysis. There may be. The transfer function A (z) of the linear prediction inverse filter is a function representing the response of the linear prediction inverse filter in a discrete-time system.

Can be represented by. p is the prediction order and α _i (i = 1, .., p) is the linear prediction coefficient. For example, a method may be used in which the time envelope rises and / or falls by filtering the conversion coefficient of the selected frequency band with a linear prediction filter using the linear prediction coefficient. The transfer function of the linear prediction filter is

Can be represented by.

In the time envelope shaping process using the linear prediction coefficient, the bandwidth expansion factor ρ may be used to adjust the intensity of flattening the time envelope or making it rise and / or fall.

The above example processes not only the conversion coefficient obtained by converting the decoded signal into a time frequency, but also the subsample of the subband signal obtained by converting the decoded signal into a signal in the frequency domain by a filter bank at an arbitrary time t. You may. In the above example, by filtering the decoded signal in the frequency domain based on linear predictive analysis, the distribution of power in the time domain of the decoded signal can be changed and the time envelope can be shaped.

Further, for example, the amplitude of the subband signal obtained by converting the decoded signal into a signal in the frequency domain by the filter bank is set to the average amplitude of the frequency component (or frequency band) to be subjected to the time wrapping shaping process in an arbitrary time segment. The time wrap may be flattened. As a result, the time envelope can be flattened while retaining the energy of the frequency component (or frequency band) of the time segment before the time envelope shaping process. Similarly, the time envelope may rise / fall by changing the amplitude of the subband signal while retaining the energy of the frequency component (or frequency band) of the time segment before the time envelope shaping process. ..

Further, for example, as shown in FIG. 13, a frequency component or frequency band not selected as a frequency component or frequency band for shaping the time wrapping by the frequency selection unit 10bB (referred to as a non-selection frequency component or non-selection frequency band). In the frequency band including, after replacing the conversion coefficient (or subsample) of the non-selective frequency component (which may be the non-selective frequency band) of the decoded signal with another value, time-wrapping shaping is performed by the above-mentioned time-wrapping shaping method. After processing, the conversion coefficient (or subsample) of the non-selected frequency component (which may be the non-selected frequency band) is returned to the original value before replacement, so that the non-selected frequency component (which may be the non-selected frequency band) may be used. ) May be applied to the frequency component (frequency band) excluding the time wrapping process.

As a result, even when the frequency component (or frequency band) to be subjected to the time-wrapping shaping process is finely divided due to the non-selection frequency component (or non-selection frequency band) being scattered, the frequency component is divided. (Or frequency band) can be collectively time-wrapped and shaped, and the amount of calculation can be reduced. For example, in the time-wrapping shaping method using the linear predictive analysis, the linear predictive analysis is performed on the frequency component (or frequency band) to which the finely divided time-wrapping shaping process is performed, whereas the divided frequency is used. The components (or frequency bands), including the non-selection frequency components (or non-selection frequency bands), may be collectively subjected to a single linear prediction analysis, and further filtered by a linear prediction inverse filter (or a linear prediction filter). The processing can also be performed by filtering the divided frequency components (or frequency bands) including the non-selection frequency components (or non-selection frequency bands) at one time, and can be realized with a low calculation amount.

The replacement of the conversion coefficient (or subsample) of the non-selection frequency component (which may be the non-selection frequency band) is, for example, the conversion coefficient (or subsample) of the non-selection frequency component (which may be the non-selection frequency band) and its subsample. The amplitude of the conversion coefficient (or subsample) of the non-selected frequency component (which may be the non-selected frequency band) may be replaced by using the average value of the amplitude including the neighboring frequency component (or the frequency band). Good. In that case, for example, the sign of the conversion coefficient may maintain the sign of the original conversion coefficient, and the phase of the subsample may maintain the phase of the original subsample. Further, for example, the conversion coefficient (or subsample) of the frequency component (which may be a frequency band) is not quantized / encoded, and the conversion coefficient (or subsample) of another frequency component (which may be a frequency band) is used. If it is selected to perform time wrapping shaping on the frequency components (which may be in the frequency band) generated by duplication / approximation or / and generation / addition of pseudo-noise signals and / or addition of sine signals. The conversion coefficient (or subsample) of the non-selection frequency component (which may be the non-selection frequency band) is duplicated / approximated by the conversion coefficient (or subsample) of another frequency component (which may be the frequency band) in a pseudo manner, or / and It may be replaced with the conversion coefficient (or subsample) generated by the generation / addition of the pseudo-noise signal and / or the addition of the sine signal. The time envelope shaping method of the selected frequency band may be combined with the above methods, and the time envelope shaping method is not limited to the above example.

The time-frequency inverse conversion unit 10bD converts the decoded signal that has undergone time-envelope shaping in a frequency-selective manner into a signal in the time domain and outputs it (step S10-2-4).
[Second Embodiment]
FIG. 14 is a diagram showing the configuration of the audio decoding device 11 according to the second embodiment. The communication device of the voice decoding device 11 receives the coding sequence in which the voice signal is encoded, and further outputs the decoded voice signal to the outside. As shown in FIG. 14, the voice decoding device 11 functionally includes a demultiplexing unit 11a, a decoding unit 10a, and a selective time envelope shaping unit 11b.

FIG. 15 is a flowchart showing the operation of the voice decoding device 11 according to the second embodiment.

The demultiplexing unit 11a separates the coded sequence into a coded sequence for obtaining a decoded signal by decoding / dequantizing the coded sequence and time-envelope information (step S11-1). The decoding unit 10a decodes the coded sequence and generates a decoded signal (step S10-1). If the time-envelope information is encoded and / and quantized, it is decoded and / and dequantized to obtain the time-envelope information.

The time-envelope information may be, for example, information indicating that the time-envelope of the input signal encoded by the coding apparatus is flat. For example, it may be information indicating that the time envelope of the input signal is a rising edge. For example, it may be information indicating that the time envelope of the input signal is falling.

Further, for example, the time-wrapping information may be information indicating the degree of flatness of the time-wrapping of the input signal, and may be, for example, information indicating the degree of rise of the time-wrapping of the input signal. For example, it may be information indicating the degree of falling edge of the time wrapping of the input signal.

Further, for example, the time envelope information may be information indicating whether or not the time envelope is shaped by the selective time envelope shaping unit.

The selective time wrapping shaping unit 11b receives the decoding-related information and the decoding signal, which are the information obtained when decoding the coded sequence from the decoding unit 10a, and receives the time wrapping information from the demultiplexing unit, and among these, the time wrapping information is received. Based on at least one, the time wrapping of the components of the decoded signal is selectively shaped into the desired time wrapping (step S11-2).

The method of the selective time envelope shaping in the selective time envelope shaping unit 11b may be the same as that of the selective time envelope shaping section 10b, for example, and the selective time envelope shaping may be performed in consideration of the time envelope information. For example, when the time envelope information is information indicating that the time envelope of the input signal encoded by the coding apparatus is flat, the time envelope may be shaped flat based on the information. For example, when the time envelope information is information indicating that the time envelope of the input signal is the rising edge, the time envelope may be shaped into the rising edge based on the information. For example, when the time envelope information is information indicating that the time envelope of the input signal is a falling edge, the time envelope may be shaped into a falling edge based on the information.

Further, for example, when the time envelope information is information indicating the degree of flatness of the time envelope of the input signal, the strength of flattening the time envelope may be adjusted based on the information. For example, when the time envelope information is information indicating the degree of rise of the time envelope of the input signal, the strength of causing the time envelope to rise may be adjusted based on the information. For example, when the time envelope information is information indicating the degree of the fall of the time envelope of the input signal, the strength of causing the time envelope to fall may be adjusted based on the information.

Further, for example, when the time envelope information is information indicating whether or not the time envelope is shaped by the selective time envelope shaping unit 11b, it is determined whether or not the time envelope shaping process is performed based on the information. You may.

Further, for example, in performing the time wrapping shaping process based on the time wrapping information in the above example, the frequency band (which may be a frequency component) to be subjected to the time wrapping shaping is selected in the same manner as in the first embodiment. , The time wrapping of the selected frequency band (which may be a frequency component) in the decoded signal may be shaped into the desired time wrapping.

FIG. 16 is a diagram showing the configuration of the voice coding device 21 according to the second embodiment. The communication device of the voice coding device 21 receives the voice signal to be coded from the outside, and further outputs the coded coding sequence to the outside. As shown in FIG. 16, the voice coding device 21 functionally includes a coding unit 21a, a time-envelope information coding unit 21b, and a multiplexing unit 21c.

FIG. 17 is a flowchart showing the operation of the voice coding device 21 according to the second embodiment.

The coding unit 21a encodes the input audio signal to generate a coded sequence (step S21-1). The audio signal coding method in the coding unit 21a is a coding method corresponding to the decoding method of the decoding unit 10a.

The time-envelope information coding unit 21b generates time-envelope information from at least one of the input voice signal and the information obtained when the voice signal is encoded by the coding unit 21a. The generated time envelope information may be encoded / quantized (step S21-2). The time-envelope information may be, for example, the time-envelope information obtained by the demultiplexing unit 11a of the voice decoding device 11.

Further, for example, when the decoding unit of the voice decoding device 11 generates a decoding signal, a process related to time envelope shaping different from the present invention is performed, and the information related to the time envelope shaping process is held in the voice coding device 21. If so, the time-envelope information may be generated using the information. For example, based on the information on whether or not to perform the time envelope processing different from that of the present invention, the selective time envelope shaping unit 11b of the voice decoding device 11 generates information indicating whether or not to shape the time envelope. You may.

Further, for example, in the selective time envelope shaping unit 11b of the voice decoding device 11, the linear prediction analysis described in the first example of the selective time envelope shaping unit 10b of the voice decoding device 10 according to the first embodiment is performed. When performing the time envelope shaping process used, the result of linear prediction analysis of the conversion coefficient (may be a subband sample) of the input voice signal is used in the same manner as the linear prediction analysis in the time envelope shaping process. May generate time-envelope information. Specifically, for example, the predicted gain by the linear prediction analysis may be calculated, and the time envelope information may be generated based on the predicted gain. When calculating the predicted gain, the conversion coefficients (which may be subband samples) of all frequency bands of the input audio signal may be linearly predicted and analyzed, and the frequency of a part of the input audio signal may be calculated. The band conversion factor (which may be a subband sample) may be linearly predicted. Further, the input audio signal may be divided into a plurality of frequency bands and a linear prediction analysis of the conversion coefficient (may be a subband sample) for each frequency band may be performed. In that case, a plurality of predicted gains may be obtained. It can be calculated, and the time wrapping information may be generated using the plurality of predicted gains.

Further, for example, when the decoding unit 10a has the configuration of the second example, the information obtained when the coding unit 21a encodes the audio signal is the coding method corresponding to the first decoding method (the first decoding method). At least one of the information obtained during coding by the coding method (1) and the information obtained by coding by the coding method (second coding method) corresponding to the second decoding method. It may be one.

The multiplexing unit 21c multiplexes and outputs the coding sequence obtained by the coding unit and the time envelope information obtained by the time envelope information coding unit (step S21-3).
[Third Embodiment]
FIG. 18 is a diagram showing the configuration of the audio decoding device 12 according to the third embodiment. The communication device of the voice decoding device 12 receives the coding sequence in which the voice signal is encoded, and further outputs the decoded voice signal to the outside. As shown in FIG. 18, the voice decoding device 12 functionally includes a decoding unit 10a and a time envelope shaping unit 12a.

FIG. 19 is a flowchart showing the operation of the voice decoding device 12 according to the third embodiment. The decoding unit 10a decodes the coded sequence and generates a decoded signal (step S10-1). Then, the time envelope shaping unit 12a shapes the time envelope of the decoding signal output from the decoding unit 10a into a desired time envelope (step S12-1). The time-wrapping shaping method is similar to the first embodiment, in which the time-wrapping is filtered by a linear prediction inverse filter using the linear prediction coefficient obtained by linear prediction analysis of the conversion coefficient of the decoded signal. It may be a flattening method, or it may be a method of making the time wrapping rise or / or fall by filtering with a linear prediction filter using the linear prediction coefficient, and further flattening using the bandwidth expansion factor. The strength of the rising edge / falling edge may be controlled, and the sub-band signal obtained by converting the decoded signal into a signal in the frequency domain by a filter bank instead of the conversion coefficient of the decoded signal is sub-banded at an arbitrary time t. The sample may be subjected to the time wrapping shaping of the above example. Further, as in the first embodiment, the amplitude of the subband signal may be modified so as to obtain a desired time envelope in an arbitrary time segment, for example, a frequency at which the time envelope shaping process is performed. The time envelope may be flattened by making the average amplitude of the components (or frequency band). The above time envelope shaping may be applied to the entire frequency band of the decoded signal, or may be applied to a predetermined frequency band.
[Fourth Embodiment]
FIG. 20 is a diagram showing the configuration of the audio decoding device 13 according to the fourth embodiment. The communication device of the voice decoding device 13 receives the coding sequence in which the voice signal is encoded, and further outputs the decoded voice signal to the outside. As shown in FIG. 20, the voice decoding device 13 functionally includes a demultiplexing unit 11a, a decoding unit 10a, and a time envelope shaping unit 13a.

FIG. 21 is a flowchart showing the operation of the voice decoding device 13 according to the fourth embodiment. The demultiplexing unit 11a separates the coded sequence into a coded sequence obtained by decoding / dequantumizing the coded sequence and time-envelope information (step S11-1), and the decoding unit 10a decodes the coded sequence. , Generates a decoding signal (step S10-1). Then, the time envelope shaping unit 13a receives the time envelope information from the demultiplexing unit 11a, and based on the time envelope information, shapes the time envelope of the decoding signal output from the decoding unit 10a into a desired time envelope ( Step S13-1).

The time wrapping information is information indicating that the time wrapping of the input signal encoded by the coding device is flat, and that the time wrapping of the input signal is rising, as in the second embodiment. The information to be shown may be information indicating that the time wrapping of the input signal is falling, and further, for example, information indicating the degree of flatness of the time wrapping of the input signal, the time wrapping of the input signal. It may be information indicating the degree of rise, information indicating the degree of fall of the time wrapping of the input signal, and further, information indicating whether or not the time wrapping shaping unit 13a shapes the time wrapping. You may.
[Hardware configuration]
The above-mentioned voice decoding devices 10, 11, 12, 13 and the voice coding device 21 are each composed of hardware such as a CPU. FIG. 11 is a diagram showing an example of the hardware configuration of each of the voice decoding devices 10, 11, 12, 13 and the voice coding device 21. The voice decoding devices 10, 11, 12, 13 and the voice coding device 21, respectively, are physically as shown in FIG. 11, the CPU 100, the main storage devices RAM 101 and ROM 102, and the input / output devices 103 such as displays. It is configured as a computer system including a communication module 104, an auxiliary storage device 105, and the like.

The voice decoding devices 10, 11, 12, 13 and the voice coding device 21 have their respective function blocks loaded with predetermined computer software on the hardware such as the CPU 100 and the RAM 101 shown in FIG. 22, respectively. This is realized by operating the input / output device 103, the communication module 104, and the auxiliary storage device 105 under the control of the CPU 100, and reading and writing data in the RAM 101.
[Program structure]
Subsequently, the above-mentioned voice decoding devices 10, 11, 12, 13 and the voice coding device 21 will explain the voice decoding program 50 and the voice coding program 60 for causing the computer to execute the processing by each.

As shown in FIG. 23, the voice decoding program 50 is inserted into a computer and accessed, or is stored in a program storage area 41 formed in a recording medium 40 included in the computer. More specifically, the voice decoding program 50 is stored in the program storage area 41 formed in the recording medium 40 included in the voice decoding device 10.

The voice decoding program 50 has the functions realized by executing the decoding module 50a and the selective time envelope shaping module 50b with the functions of the decoding unit 10a and the selective time envelope shaping unit 10b of the voice decoding device 10 described above, respectively. The same is true. Further, the decoding module 50a includes a module for functioning as a decoding / inverse quantization unit 10aA, a decoding-related information output unit 10aB, and a time-frequency inverse conversion unit 10aC. Further, the decoding module 50a may include a module for functioning as a coded sequence analysis unit 10aD, a first decoding unit 10aE, and a second decoding unit 10aF.

Further, the selective time wrapping shaping module 50b includes a module for functioning as a time frequency conversion section 10bA, a frequency selection section 10bB, a frequency selective time wrapping shaping section 10bC, and a time frequency inverse conversion section 10bD.

Further, the voice decoding program 50 includes a module for functioning as a demultiplexing unit 11a, a decoding unit 10a, and a selective time envelope shaping unit 11b in order to function with the above-mentioned voice decoding device 11.

Further, the voice decoding program 50 includes a module for functioning as a decoding unit 10a and a time envelope shaping unit 12a in order to function as the above-mentioned voice decoding device 12.

Further, the voice decoding program 50 includes a module for functioning as a demultiplexing unit 11a, a decoding unit 10a, and a time envelope shaping unit 13a in order to function as the voice decoding device 13.

Further, as shown in FIG. 24, the voice coding program 60 is inserted into a computer and accessed, or is stored in a program storage area 41 formed in a recording medium 40 included in the computer. More specifically, the voice coding program 60 is stored in the program storage area 41 formed on the recording medium 40 included in the voice coding device 20.

The voice coding program 60 includes a coding module 60a, a time-envelope information coding module 60b, and a multiplexing module 60c. The functions realized by executing the coding module 60a, the time-wrapping information coding module 60b, and the multiplexing module 60c are the coding unit 21a and the time-wrapping information coding unit 21b of the voice coding device 21 described above. And the functions of the multiplexing unit 21c are the same.

A part or all of the voice decoding program 50 and the voice coding program 60 are transmitted via a transmission medium such as a communication line, and are received and recorded (including installation) by another device. May be. Further, each module of the voice decoding program 50 and the voice coding program 60 may be installed on any of a plurality of computers instead of one computer. In that case, each of the above-mentioned voice decoding program 50 and voice coding program 60 is processed by the computer system by the plurality of computers.

One aspect of the voice decoding device and the voice coding device in the present embodiment will be specified as follows.

The voice decoding device according to one aspect of the present invention is a voice decoding device that decodes a coded voice signal and outputs a voice signal, and decodes a coded sequence including the coded voice signal. It includes a decoding unit that obtains a decoding signal, and a selective time wrapping shaping unit that shapes the time wrapping of the frequency band in the decoding signal based on the decoding-related information regarding the decoding of the coded sequence. The time envelope of a signal represents a variation in the energy or power (and equivalent parameters) of the signal in the time direction. With this configuration, the time envelope of the decoded signal in the frequency band encoded with a small number of bits can be shaped into a desired time envelope, and the quality can be improved.

Further, the audio decoding device according to another aspect of the present invention is an audio decoding device that decodes a coded audio signal and outputs an audio signal, and is a coding sequence including the encoded audio signal. And a demultiplexing unit that separates the time wrapping information related to the time wrapping of the audio signal, a decoding unit that decodes the coded sequence to obtain a decoded signal, and a decoding related unit relating to the decoding of the time wrapping information and the coded sequence. A selective time-wrapping shaping unit that shapes the time-wrapping of the frequency band in the decoded signal based on at least one of the information is provided. With this configuration, the number of bits is small based on the time wrapping information generated by referring to the voice signal input to the voice coding device in the voice coding device that generates and outputs the coded sequence of the voice signal. It is possible to shape the time wrapping of the decoded signal in the encoded frequency band into a desired time wrapping and improve the quality.

The decoding unit is a decoding / dequantization unit that decodes / / and dequantizes the coded sequence to obtain a decoding signal in the frequency domain, and a decoding / / dequantization process in the decoding / dequantization unit. A decoding-related information output unit that outputs at least one of the obtained information and information obtained by analyzing the coding sequence as decoding-related information, and a decoding-related information output unit that converts the decoding signal in the frequency domain into a signal in the time domain. It may be provided with a time-frequency inverse conversion unit for output. With this configuration, the time envelope of the decoded signal in the frequency band encoded with a small number of bits can be shaped into a desired time envelope, and the quality can be improved.

Further, the decoding unit includes a coding sequence analysis unit that separates the coding sequence into a first coding sequence and a second coding sequence, and a first decoding unit that decodes or / or inversely quantizes the first coding sequence. A second decoding signal is obtained and output by using a first decoding unit that obtains a signal and obtains first decoding-related information as the decoding-related information, and at least one of the second coding series and the first decoding signal. , A second decoding unit that outputs the second decoding-related information may be provided as the decoding-related information. With this configuration, even when a decoded signal is generated by being decoded by a plurality of decoding units, the time envelope of the decoded signal in the frequency band encoded with a small number of bits is shaped into a desired time envelope, and the quality is improved. It becomes possible to do.

The first decoding unit is a first decoding / dequantization unit that decodes and / and dequantizes the first coding sequence to obtain a first decoding signal, and a decoding / / / decoding in the first decoding / dequantization unit. And a first decoding-related information output unit that outputs at least one of the information obtained in the process of inverse quantization and the information obtained by analyzing the first coding sequence as the first decoding-related information. It may be that. According to this configuration, when the decoding signal is generated by being decoded by a plurality of decoding units, the time of the decoding signal in the frequency band encoded with a small number of bits based on at least the information related to the first decoding unit. It is possible to shape the envelope into a desired time envelope and improve the quality.

The second decoding unit includes a second decoding / dequantization unit that obtains a second decoding signal using at least one of the second coding series and the first decoding signal, and the second decoding / dequantization unit. A second decoding-related information output unit that outputs at least one of the information obtained in the process of obtaining the second decoding signal in the unit and the information obtained by analyzing the second coding sequence as the second decoding-related information. May be provided. According to this configuration, when the decoding signal is generated by being decoded by a plurality of decoding units, the time of the decoding signal in the frequency band encoded with a small number of bits based on at least the information related to the second decoding unit. It is possible to shape the envelope into a desired time envelope and improve the quality.

The selective time wrapping shaping unit shapes the time wrapping of the decoding signal in the frequency domain in each frequency band based on the time / frequency conversion unit that converts the decoded signal into a signal in the frequency domain and the decoding-related information. It may be provided with a frequency-selective time-environment shaping unit and a time-frequency inverse conversion unit that converts a decoded signal in the frequency domain in which the time-wrapping of each frequency band is shaped into a signal in the time domain. With this configuration, the time envelope of the decoded signal in the frequency band encoded with a small number of bits in the frequency domain can be shaped into a desired time envelope, and the quality can be improved.

The decoding-related information may be information related to the number of coding bits in each frequency band. With this configuration, it is possible to shape the time envelope of the decoded signal of the frequency band into a desired time envelope according to the number of coded bits of each frequency band, and improve the quality.

The decoding-related information may be information related to the quantization step of each frequency band. With this configuration, it is possible to shape the time envelope of the decoded signal of the frequency band into a desired time envelope according to the quantization step of each frequency band, and improve the quality.

The decoding-related information may be information related to the coding method of each frequency band. With this configuration, it is possible to shape the time envelope of the decoded signal of the frequency band into a desired time envelope according to the coding method of each frequency band, and improve the quality.

Decoding-related information may be information related to noise components injected into each frequency band. With this configuration, it is possible to shape the time envelope of the decoded signal of the frequency band into a desired time envelope according to the noise component injected into each frequency band, and improve the quality.

The frequency-selective time-wrapping shaping unit desires the decoding signal corresponding to the frequency band for shaping the time-wrapping by using a filter using a linear prediction coefficient obtained by linearly predicting and analyzing the decoding signal in the frequency domain. It may be shaped into the time wrapping of. With this configuration, it is possible to improve the quality by shaping the time wrapping of the decoding signal of the frequency band encoded with a small number of bits into a desired time wrapping by using the decoding signal in the frequency domain.

The frequency-selective time-wrapping shaping unit corresponds to a frequency that shapes the time-wrapping and a frequency that does not shape the time-wrapping after replacing the decoded signal corresponding to the frequency band that does not shape the time-wrapping with another signal in the frequency region. Using a filter using the linear prediction coefficient obtained by linear predictive analysis of the decoded signal in the frequency region, the decoded signal corresponding to the frequency that shapes the time envelope and the frequency that does not shape the time envelope is filtered in the frequency region. By processing, it may be shaped into a desired time wrapping, and after the time wrapping shaping, the decoded signal corresponding to the frequency band in which the time wrapping is not shaped may be returned to the original signal before being replaced with another signal. With this configuration, the time wrapping of the decoding signal in the frequency band encoded with a small number of bits is shaped into the desired time wrapping by using the decoding signal in the frequency domain with a smaller amount of calculation, and the quality is improved. Is possible.

Further, the voice decoding device according to another aspect of the present invention is a voice decoding device that decodes a coded voice signal and outputs a voice signal, and is a coding sequence including the coded voice signal. By using a decoding unit that obtains a decoded signal by decoding the decoded signal and a filter that uses a linear prediction coefficient obtained by linearly predicting and analyzing the decoded signal in the frequency domain, the decoded signal is filtered in the frequency domain. It is provided with a time-wrapping shaping unit for shaping into a desired time-wrapping. With this configuration, it is possible to improve the quality by shaping the time envelope of the decoded signal encoded with the small number of bits into a desired time envelope by using the decoded signal in the frequency domain.

Further, the voice coding device according to another aspect of the present invention is a voice coding device that encodes an input voice signal and outputs a coded sequence, and encodes the voice signal and outputs the voice signal. A coding unit that obtains a coding sequence including the above, a time-wrapping information coding unit that encodes information regarding the time-wrapping of the voice signal, a coding sequence obtained by the coding unit, and the time-wrapping information coding. It is provided with a multiplexing unit that multiplexes a coding sequence of information regarding the time wrapping obtained by the unit.

Further, an aspect according to one aspect of the present invention can be grasped as a voice decoding method, a voice coding method, a voice decoding program, and a voice coding program as follows.

That is, the audio decoding method according to one aspect of the present invention is an audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs an audio signal, and is a code including the encoded audio signal. It includes a decoding step of decoding a coding sequence to obtain a decoding signal, and a selective time-wrapping shaping step of shaping the time wrapping of a frequency band in the decoding signal based on the decoding-related information regarding the decoding of the coded sequence.

Further, the audio decoding method according to one aspect of the present invention is an audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs an audio signal, and is a code including the encoded audio signal. The demultiplexing step of separating the time-wrapping information related to the time-wrapping of the audio signal and the audio signal, the decoding step of decoding the coded sequence to obtain the decoding signal, and the decoding of the time-wrapping information and the coded sequence. It comprises a selective time wrapping shaping step that shapes the time wrapping of the frequency band in the decoding signal based on at least one of the decoding related information.

Further, the audio decoding program according to one aspect of the present invention is based on a decoding step of decoding a coded sequence including the coded audio signal to obtain a decoded signal and decoding-related information regarding decoding of the coded sequence. Then, the computer is made to perform a selective time wrapping shaping step of shaping the time wrapping of the frequency band in the decoded signal.

Further, the audio decoding method according to one aspect of the present invention is an audio decoding method of an audio decoding device that decodes an encoded audio signal and outputs an audio signal, and is a code including the encoded audio signal. The demultiplexing step of separating the time-wrapping information related to the time-wrapping of the audio signal and the audio signal, the decoding step of decoding the coded sequence to obtain the decoding signal, and the decoding of the time-wrapping information and the coded sequence. Have the computer perform a selective time-wrapping shaping step that shapes the time-wrapping of the frequency band in the decoding signal based on at least one of the decoding-related information.

Further, the voice decoding method according to one aspect of the present invention is a voice decoding method of a voice decoding device that decodes a coded voice signal and outputs a voice signal, and is a code including the coded voice signal. The decoded signal is filtered in the frequency domain using a decoding step of decoding the coding sequence to obtain a decoded signal and a filter using the linear prediction coefficient obtained by linearly predicting and analyzing the decoded signal in the frequency domain. This includes a time-encapsulation shaping step of shaping into a desired time-encapsulation.

Further, the voice coding method according to one aspect of the present invention is a voice coding method of a voice coding device that encodes an input voice signal and outputs a coded sequence, and encodes the voice signal. A coding step for obtaining a coded sequence including the voice signal, a time-wrapping information coding step for coding information regarding the time-wrapping of the voice signal, a coding sequence obtained in the coding step, and the time-wrapping. It includes a multiplexing step that multiplexes a coding sequence of information about the time wrapping obtained in the information coding step.

Further, the voice decoding program according to one aspect of the present invention obtains a decoding step of decoding a coded sequence including a coded voice signal to obtain a decoded signal and linearly predicting and analyzing the decoded signal in the frequency domain. Using a filter using the obtained linear prediction coefficient, the computer is made to perform a time-wrapping shaping step of shaping the decoded signal into a desired time-wrapping by filtering in the frequency domain.

Further, the voice coding program according to one aspect of the present invention includes a coding step of coding a voice signal to obtain a coding sequence including the voice signal, and a time inclusion of coding information regarding the time inclusion of the voice signal. The computer is made to execute the information coding step, the coding sequence obtained in the coding step, and the multiplexing step for multiplexing the coding sequence of the information related to the time inclusion obtained in the time-wrapping information coding step.

10aF-1 ... Inverse quantization unit, 10 ... Voice decoding device, 10a ... Decoding unit, 10aA ... Decoding / inverse quantization unit, 10aB ... Decoding related information output unit, 10aC ... Time frequency inverse conversion unit, 10aD ... Coding sequence Analysis unit, 10aE ... 1st decoding unit, 10aE-a ... 1st decoding / dequantization unit, 10aE-b ... 1st decoding-related information output unit, 10aF ... 2nd decoding unit, 10aF-a ... 2nd decoding / Inverse quantization unit, 10aF-b ... Second decoding-related information output unit, 10aF-c ... Decoding signal synthesis unit, 10b ... Selective time entrainment shaping unit, 10bA ... Time frequency conversion unit, 10bB ... Frequency selection unit, 10bC ... Frequency selective time wrapping shaping unit, 10bD ... Time frequency inverse conversion unit, 11 ... Voice decoding device, 11a ... Demultiplexing section, 11b ... Selective time wrapping shaping unit, 12 ... Voice decoding device, 12a ... Time wrapping shaping unit , 13 ... voice decoding device, 13a ... time wrapping shaping unit, 21 ... voice coding device, 21a ... coding unit, 21b ... time wrapping information coding unit, 21c ... multiplexing unit.

Claims (2)

An audio decoding device that decodes an encoded audio signal and outputs an audio signal.
A decoding unit that decodes a coded sequence including the coded audio signal to obtain a decoded signal, and
A selective time envelope shaping unit that shapes the time envelope of the frequency band in the decoded signal based on the decoding-related information regarding the decoding of the coded sequence.
With
The decoding unit obtains a decoded signal by duplicating a signal in a frequency band different from the frequency band in a part of the frequency band.
The selective time envelope shaping unit replaces the decoded signal corresponding to a frequency band that does not shape the time envelope with another signal in the frequency domain.
Audio decoding device. It is a voice decoding method of a voice decoding device that decodes a coded voice signal and outputs a voice signal.
A decoding step of decoding a coded sequence including the encoded audio signal to obtain a decoded signal, and
A selective time envelope shaping step that shapes the time envelope of the frequency band in the decoded signal based on the decoding-related information regarding the decoding of the coded sequence.
With
In the decoding step, a decoding signal is obtained by duplicating a signal in a frequency band different from the frequency band in a part of the frequency band.
The selective time envelope shaping step replaces the decoded signal corresponding to a frequency band that does not shape the time envelope with another signal in the frequency domain.
Audio decoding method.

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