JP2007272238A - Encoding device and method, decoding device and method, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow encoding to be performed in such a manner that the occurrence of pre-echo and post-echo is suppressed. <P>SOLUTION: A predetermined waveform analysis is performed to a low-frequency-component input time-series signal which includes a high-frequency component occurring at a specific time, and a low-frequency-component time-series signal as shown in Fig.9A is generated, based on the analysis result. The low-frequency-component time-series signal is removed from the input time-series signal to generate a residual time-series signal as shown in Fig.9B. Amplitude control is performed such that the amplitude of the residual time-series signal is made almost constant in a block which serves as a unit of encoding to generate a time-series signal to be quantized as shown in Fig.9C. The time-series signal to be quantized is quantized and encoded. The present invention can be applied to audio recording and reproduction apparatuses. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an encoding apparatus and method, a decoding apparatus and method, and a recording medium, and more particularly to an encoding apparatus and method, a decoding apparatus and method, and a recording medium that can suppress the occurrence of pre-echo and post-echo.

  FIG. 1 shows a configuration example of a conventional encoding device 1 and decoding device 2.

  The acoustic time series signal SS supplied to the encoding device 1 is input to the amplitude operation unit 11.

The amplitude operation unit 11 divides the input acoustic time-series signal SS into blocks (fixed length) that are units of encoding, divides the block into a plurality of blocks, and generates sub-blocks. Every time, the amplitude of the acoustic time series signal SS is analyzed. Based on the amplitude analysis result, the amplitude operation unit 11 generates amplitude operation information G used in the amplitude operation for making the amplitude in the block substantially constant. For example, when the acoustic time-series signal SS in the block includes a locally generated high frequency component as shown in FIG. 2A, the amplitude operation unit 11 starts from the amplitude H _{1 at} time t ₀ . the amplitude H _2, at time t _1, recognizes that it has changed significantly from the amplitude H ₂ to the amplitude H _1, it generates an amplitude operation information G indicating that.

  The amplitude operation unit 11 outputs the generated amplitude operation information G to the code string generation unit 14, and operates the amplitude of the acoustic time series signal SS for each sub-block based on the amplitude operation information G. That is, the amplitude operation unit 11 generates a time series signal GS in which the amplitude in the block is substantially constant, and outputs it to the spectrum conversion unit 12.

In the case of the example in FIG. 2, the operation unit 11 converts the amplitude H ₁ up to time t ₀ and the amplitude H ₁ from time t ₁ to the amplitude H ₁ for the acoustic time series signal SS in the block shown in FIG. _The amplitude operation to amplify to ₂ is performed, and the resulting time series signal GS with substantially constant amplitude in the block as shown in FIG. 2B is output to the spectrum conversion unit 12.

  The spectrum conversion unit 12 decomposes the time series signal GS from the amplitude operation unit 11 into a spectrum F, which is a frequency component, in accordance with MDCT (Modified Discrete Cosine Transform) and the like, and the spectrum F is converted into a normalization / quantization unit 13. Output.

  The normalization / quantization unit 13 analyzes the spectrum F from the spectrum conversion unit 12 and generates normalization information N. The normalization / quantization unit 13 outputs the generated normalization information N to the code string generation unit 14 and normalizes the spectrum F based on the normalization information N.

  The normalization / quantization unit 13 also outputs predetermined quantization information Q to the code string generation unit 14, quantizes the normalized spectrum F based on the quantization information Q, and obtains the result. The obtained spectrum information QF is output to the code string generator 14.

  The code sequence generation unit 14 encodes the amplitude operation information G from the amplitude operation unit 11 and the normalization information N, quantization information Q, and spectrum information QF from the normalization / quantization unit 13 to generate a code sequence CD. Is generated. The generated code string CD is supplied to the decoding device 2.

  The code string CD supplied to the decoding device 2 is input to the code string decomposing unit 21.

  The code string decomposing unit 21 decomposes the input code string CD into spectrum information QF, quantization information Q, normalization information N, and amplitude operation information G, and also includes spectrum information QF, quantization information Q, and normal information. The quantization information N is output to the inverse quantization / inverse normalization unit 21, and the amplitude operation information G is output to the inverse amplitude operation unit 24.

  The inverse quantization / inverse normalization unit 22 inversely quantizes the spectrum information QF input from the code string decomposition unit 21 based on the quantization information Q, and further performs inverse normalization based on the normalization information N. At the same time, the spectrum F ′ corresponding to the spectrum F generated by the encoding device 1 (spectrum conversion unit 12) obtained as a result is output to the inverse spectrum conversion unit 23.

  The inverse spectrum transform unit 23 inversely transforms the spectrum F ′ from the inverse quantization / inverse normalization unit 22 into a time-series signal in accordance with IMDCT (Inverse MDCT), and the result obtained The time-series signal GS ′ corresponding to the time-series signal GS generated by the encoding apparatus 1 (amplitude operation unit 11) is output to the inverse amplitude operation unit 24.

  For example, a time series signal GS ′ corresponding to the time series signal GS shown in FIG. 2B is generated and output to the inverse amplitude operation unit 24.

  The inverse amplitude operation unit 24 performs an amplitude operation on the time series signal GS ′ from the inverse spectrum conversion unit 23 based on the amplitude operation information G from the code string decomposition unit 21, that is, the encoding device 1 (amplitude operation unit 11). In contrast to the amplitude operation performed in step 1, the amplitude operation in which the amplitude is operated is performed, and the acoustic time series signal SS ′ corresponding to the acoustic time series signal SS input to the encoding device 1 obtained as a result is obtained. Is output to the outside.

  For example, an acoustic time series signal SS ′ corresponding to the acoustic time series signal SS shown in FIG. 2A is generated and output to the outside.

As described above, in the encoding device 1, the small amplitude portion of the acoustic time series signal SS (for example, the portion of the amplitude H ₁ in the acoustic time series signal SS in FIG. 2A) is amplified, and the amplitude in the block is made substantially constant. The code sequence is decoded by performing the amplitude operation (for example, FIG. 2B) to be performed, and performing the amplitude operation to restore the amplified portion in the decoding device 2. Generation of pre-echo and post-echo that can be heard without noise being masked by a small amplitude signal is suppressed.

However, for example, the acoustic time series signal SS in the block includes a high frequency component generated at a local time as shown in FIG. 3B, and a low frequency component time series with a large amplitude H ₁₁ as shown in FIG. 3A. when a signal encoding device 1 (the amplitude operation unit 11), by the amplitude analysis for the acoustic time-series signal SS, the amplitude in the block is detected to be constant in amplitude H _11.

  That is, in the encoding device 1, the amplitude operation for amplifying the small amplitude portion is not performed, and the time-series signal GS similar to the acoustic time-series signal SS (FIGS. 3A and 3C) is generated, and this is converted into a spectrum converted, normalized Since the code sequence is decoded without performing the amplitude operation for returning the amplitude to the original in the decoding apparatus 2, the spread high frequency as shown in FIG. 3D is eventually obtained. The acoustic time-series signal SS ′ including the component quantization noise is generated as shown in FIG. 3C. For example, in FIG. End up.

  As described above, the conventional encoding device 1 and decoding device 2 have a problem that pre-echo and post-echo suppression is not appropriately performed.

  The present invention has been made in view of such a situation, and enables the acoustic time-series signal SS to be encoded and decoded so that the pre-echo and the post-echo are appropriately suppressed. It is.

  The first encoding apparatus of the present invention performs a predetermined frequency analysis on the input time-series signal in the block, a classification means for dividing the input time-series signal into blocks of a predetermined length, and the analysis result Waveform information generating means for generating waveform information based on the signal, a residual signal generating means for removing a signal based on the waveform information from the input time-series signal in the block, and generating a residual signal; Analyzing the amplitude, performing the predetermined amplitude operation on the residual signal according to the predetermined amplitude operation information based on the analysis result, and an amplitude operation means for generating the quantization target signal, and quantizing the quantization target signal A quantization means for generating a quantized signal; and a code string generation means for generating a code string by encoding the waveform information, the amplitude operation information, and the quantized signal.

  A second encoding apparatus according to the present invention performs a predetermined frequency analysis on a signal in a block of at least one band signal, and generates waveform information based on the analysis result, and waveform information A residual signal generating means for generating a residual signal by removing the signal based on the band signal, and analyzing the amplitude of the residual signal, and according to predetermined amplitude operation information based on the analysis result, And an amplitude operation means for generating a quantization target signal by performing a predetermined amplitude operation.

  The third encoding apparatus of the present invention performs a predetermined frequency analysis on the input time-series signal in the block, a classification means for dividing the input time-series signal into blocks of a predetermined length, and the analysis result A waveform information generating means for generating waveform information based on the signal, a residual signal generating means for generating a residual signal by removing a signal based on the waveform information from the input time-series signal in the block, and a residual signal It is characterized by comprising quantization means for converting to frequency components and quantizing to generate a quantized signal, and code string generating means for encoding waveform information and the quantized signal to generate a code string.

  The encoding method of the present invention includes a step of dividing an input time-series signal into blocks of a predetermined length, a predetermined frequency analysis on the input time-series signal in the block, and based on the analysis result A waveform information generation step for generating waveform information, a residual signal generation step for generating a residual signal by removing a signal based on the waveform information from the input time series signal in the block, and analyzing the amplitude of the residual signal Then, according to the predetermined amplitude operation information based on the analysis result, the predetermined amplitude operation is performed on the residual signal to generate the quantization target signal, the quantization target signal is quantized, and the quantization target signal is quantized. A quantization step for generating a quantized signal; and a code sequence generating step for generating a code sequence by encoding the waveform information, the amplitude operation information, and the quantized signal.

  The first program of the recording medium of the present invention includes a step of dividing an input time-series signal into blocks of a predetermined length, and a predetermined frequency analysis for the input time-series signal in the block, and the analysis A waveform signal generating step for generating waveform information based on the result; a residual signal generating step for generating a residual signal by removing a signal based on the waveform information from the input time-series signal in the block; and a residual signal An amplitude operation step for generating a quantization target signal by performing a predetermined amplitude operation on the residual signal in accordance with predetermined amplitude operation information based on the analysis result, and quantizing the quantization target signal And a quantizing step for generating a quantized signal, and a code string generating step for generating a code string by encoding the waveform information, the amplitude operation information, and the quantized signal.

  In the first encoding device, the encoding method, and the first program of the present invention, the input time-series signal is divided into blocks having a predetermined length, and the input time-series signal in the block has a predetermined value. Frequency analysis is performed, waveform information is generated based on the analysis result, a signal based on the waveform information is removed from the input time series signal in the block, a residual signal is generated, and the amplitude of the residual signal is Analyzing and performing a predetermined amplitude operation on the residual signal according to the predetermined amplitude operation information based on the analysis result to generate a quantization target signal, quantizing the quantization target signal, The code string is generated by encoding the waveform information, the amplitude operation information, and the quantized signal.

  A first decoding apparatus according to the present invention includes a decomposing unit that decomposes a code string into waveform information, amplitude operation information, and a quantized signal, an inverse quantizing unit that dequantizes the quantized signal, and an inverse quantization. Inverse amplitude operation means for generating an amplitude-operated signal by performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information, and an amplitude operation for the signal generated according to the waveform information. And a time-series signal generating means for generating a time-series signal based on the received signal.

  The second decoding apparatus of the present invention includes a decomposing unit that decomposes a code string into waveform information, amplitude operation information, and a quantized signal, an inverse quantizing unit that dequantizes the quantized signal, and an inverse quantization. Inverse amplitude operation means for generating an amplitude-operated signal by performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information, and an amplitude operation for the signal generated according to the waveform information. And a time-series signal generating means for generating a time-series signal based on the received signal.

  According to the third decoding apparatus of the present invention, a decomposing unit that decomposes a code string into waveform information and a quantized signal, an inverse frequency converting unit that performs inverse frequency conversion by dequantizing the quantized signal, and in accordance with the waveform information A time-series signal generating unit that generates a time-series signal based on the generated signal and the signal subjected to inverse frequency conversion is provided.

  The decoding method of the present invention includes a decomposition step for decomposing a code string into waveform information, amplitude operation information, and a quantized signal, an inverse quantization step for dequantizing the quantized signal, and an inverse quantized signal. On the other hand, according to the amplitude operation information, an inverse amplitude operation step for generating an amplitude-controlled signal by performing an amplitude operation opposite to that at the time of encoding, a signal generated according to the waveform information, and an amplitude-controlled signal, And a time-series signal generation step of generating a time-series signal based on the above.

  The program of the second recording medium of the present invention includes a decomposition step that decomposes a code string into waveform information, amplitude operation information, and a quantized signal, an inverse quantization step that inversely quantizes the quantized signal, An inverse amplitude operation step for generating an amplitude-operated signal by performing an amplitude operation on the quantized signal according to the amplitude operation information in accordance with the amplitude operation information, and the signal and amplitude generated according to the waveform information And a time-series signal generating step of generating a time-series signal corresponding to the encoded time-series signal based on the operated signal.

  In the first decoding apparatus, the decoding method, and the program of the second recording medium of the present invention, the code string is decomposed into waveform information, amplitude operation information, and a quantized signal, and the quantized signal is dequantized. The inversely quantized signal is subjected to the amplitude operation opposite to that at the time of encoding in accordance with the amplitude operation information to generate an amplitude-operated signal, and the amplitude operation is performed on the signal generated according to the waveform information. Based on the received signal, a time series signal corresponding to the encoded time series signal is generated.

  According to the present invention, the occurrence of pre-echo and post-echo can be suppressed.

  FIG. 4 shows a configuration example of the encoding device 31 to which the present invention is applied. This encoding device 31 is provided with a residual time series signal generation unit 32 in the preceding stage of the amplitude operation unit 11 of the encoding device 1 of FIG. Other configurations are the same as those in FIG. 1, and the description thereof will be omitted as appropriate.

  A residual time series signal generation unit (hereinafter abbreviated as a generation unit) 32 divides the input acoustic time series signal SS into blocks that are units of encoding, and performs predetermined frequency analysis for each block. The waveform information E is generated based on the analysis result.

  The generation unit 32 outputs the generated waveform information E to the code string generation unit 14, and subtracts (removes) the low-frequency component time series signal ES generated based on the waveform information E from the acoustic time series signal SS. A residual time series signal RS is generated and output to the amplitude operation unit 11. That is, the low frequency component of the acoustic time series signal SS is removed and supplied to the amplitude operation unit 11 as the residual time series signal RS.

  The amplitude operation unit 11 analyzes the amplitude of the residual time series signal RS from the generation unit 32 for each sub-block, and based on the analysis result, amplitude operation information G for keeping the amplitude in the block substantially constant. Is generated.

  The amplitude operation unit 11 outputs the generated amplitude operation information G to the code string generation unit 14, and on the basis of this, operates the amplitude of the residual time series signal RS for each sub-block, and is obtained as a result. The time-series signal GS whose amplitude in the block is substantially constant is output to the spectrum converter 12.

  The code string generation unit 14 includes waveform information E from the generation unit 32, amplitude operation information G from the amplitude operation unit 11, normalization information N from the normalization / quantization unit 13, quantization information Q, and spectrum. The information QF is supplied, and the encoding generation unit 14 encodes the information to generate a code string CD. The generated encoded CD is supplied to a decoding device 51 (FIG. 11) described later.

  FIG. 5 shows a configuration example of the generation unit 32. The acoustic time series signal SS is input to the frequency analysis unit 41 and the subtracter 43.

  The frequency analysis unit 41 performs frequency analysis on the acoustic time series signal SS divided into blocks by a not shown division unit, and generates a waveform for generating a low frequency component time series signal ES based on the analysis result. Information E is generated and output to the low-frequency component time-series signal generation unit 42 and the code string generation unit 14 (FIG. 4).

  A low frequency component time series signal generation unit (hereinafter abbreviated as a generation unit) 42 generates a low frequency component time series signal ES based on the waveform information E from the frequency analysis unit 41 and outputs the low frequency component time series signal ES to the subtractor 43. .

  The subtractor 43 subtracts the low-frequency component time-series signal ES from the generation unit 42 from the input acoustic time-series signal SS on the time axis, and an amplitude operation is performed on the residual time-series signal RS obtained as a result. To the unit 11.

  Next, operation | movement of the production | generation part 32 is demonstrated with reference to the flowchart of FIG. In step S1, the frequency analysis unit 41 performs an FFT analysis on the acoustic time-series signal SS in the block, and in step S2, determines a frequency range used for generating the waveform information E based on the analysis result. To do.

For example, when FFT analysis is performed on an acoustic time series signal SS having a large amplitude as shown in FIG. 7A, a distribution as shown in FIG. 7B is obtained. In this case, the frequency analysis unit 41, as a result of the analysis, two peaks are present, the first frequency showing the minimum value between the peak and the second peak of the (1st) is f _m distribution Detect that it was obtained. From the detection result, the frequency analysis unit 41 determines 0 to the frequency f _m (the range indicated by the left and right arrows in FIG. 7B) as the frequency range used for generating the waveform information E.

In step S3, the frequency analysis unit 41 calculates expression (1) to calculate the pure sound waveform Q (t) of the processing target frequency f _p within the frequency range determined in step S2, and the acoustic in the block. Equation (2) is calculated using the time series signal SS as the processing target time series signal x (t), and the residual component RS (t) is calculated.

Q (t) = Ssin (2π × f p × t) -Ccos (2π × f p × t) ... (1)
RS (t) = x (t) −Q (t) (2)

Wherein (1), f _p is the processing target frequency, S is the amplitude of the sin term pure sound waveform is a value determined by the equation (3), C is the amplitude of the cos term of net sound waveform is , Is a value obtained by equation (4), and L is the length of the block.

  Next, in step S4, the frequency analysis unit 41 calculates Equation (5) to calculate the energy (hereinafter referred to as residual energy) R of the residual component RS (t) calculated in step S3.

In step S5, the frequency analysis unit 41 calculates the residual component RS (t) calculated in step S3, the processing target frequency f _p , the amplitude S, and the amplitude C used at that time, and the residual energy R calculated in step S4. Are stored in association with each other.

Next, in step S6, the frequency analysis unit 41 determines whether or not the residual energy R for the processing target time series signal x (t) has been calculated for all the pure sound waveforms of the processing target frequencies f _p. processed frequency f if is determined that _p of not calculated for pure sound waveform, the process returns to step S3, executes the processing of steps S3 to S5 for pure sound waveform processed next frequency f _p.

When it is determined in step S6 that the residual energy R has been calculated for all the pure sound waveforms of the processing target frequency f _p , the process proceeds to step S7, and the frequency analysis unit 41 calculates in step S4 (stored in step S5). The minimum value of the residual energy R (hereinafter referred to as residual energy _Rmin ) is detected, and _fmin , _Smin , and _Cmin are stored. Here, f _min is the processing target frequency f _p when the residual energy R _min is calculated, S _min is a value obtained by Equation (6), and C _min is obtained by Equation (7). Value. X (t) in the equations (6) and (7) is “current x (t)”.

Next, in step S8, the frequency analysis unit 41 determines whether or not the residual energy R _min detected in step S7 is smaller than a predetermined threshold value W. If it is determined that the residual energy R _min is not small, the process proceeds to step S9. Equation (8) is calculated to calculate the next processing target time series signal x (t).

Next x (t) = Current x (t) −S _min sin (2π × f _min × t) −C _min sin (2π × f _min × t)
(8)

  Then, it returns to step S3 and the frequency analysis part 41 performs the process after it.

If it is determined in step S8 that the residual energy R _min is smaller than the threshold value W, the process proceeds to step S10, and the frequency analysis unit 41 stores the data stored in step S7 as shown in FIG. f _n , amplitude S _n , and amplitude C _n are output to the generation unit 42 as waveform information E.

  In addition, the process of step S1 thru | or step S10 which the frequency analysis part 41 performs follows the general harmonic analysis method which Wiener proposed. General harmonic analysis is described in N. Weiner, "The Fourier integral and certain of its applications", Dover Publications, Inc., (1958).

  Next, in step S11, the generation unit 42 calculates Equation (9) using the waveform information E from the frequency analysis unit 41 to generate a low frequency component time series signal ES (t), and Is output to the subtracter 43.

  For example, when the acoustic time-series signal SS in the block is a signal composed of low frequency components as shown in FIG. 7A, the waveform information E obtained as a result of the execution of steps S1 to S11 by the frequency analysis unit 41 is included in the waveform information E. Accordingly, a low frequency component time series signal ES (t) as shown in FIG. 9A is generated.

  In step S12, the subtractor 43 subtracts the low-frequency component time-series signal ES (t) from the generation unit 42 from the input acoustic time-series signal SS on the time axis to obtain a residual time-series signal RS ( t) is generated and output to the amplitude operation unit 11. That is, for example, the low-frequency component time series signal ES shown in FIG. 9A is subtracted from the acoustic time series signal SS shown in FIG. 7A, and the resulting residual time series signal RS (t as shown in FIG. 9B is obtained. ) Is output to the operation amplitude unit 11.

  Since the residual time series signal RS consisting only of high frequency components is supplied to the amplitude operation unit 11 in this way, the amplitude operation unit 11 compares the residual time series signal RS with respect to the residual time series signal RS. The amplitude operation is performed by amplifying the small amplitude portion and the amplitude in the block becomes substantially constant, and as a result, a time series signal GS in which the amplitude in the block becomes almost constant as shown in FIG. 9C is generated. Is done.

  Note that the frequency analysis unit 41 accumulates data every time the processing from step S3 to step S6 is repeated in step S5, but YES is determined in step S6, and the processing in step S5 is performed via step S9. In the case of executing again, the data stored until then is erased and then stored.

Further, in the above, the processing target frequency f _n, the amplitude S _n, and the amplitude C _n is output to the generation unit 42 as the waveform information E, by calculating the equation (10) and (11), the amplitude A 10 and the phase P can be calculated, and the processing target frequency f _n , amplitude A _n , and phase P _n can be supplied as waveform information E to the generating unit 42 as shown in FIG. In this case, in step S12, the generation unit 42 calculates Equation (12) instead of Equation (9) to calculate the low-frequency component time series signal ES (t).

Further, in the above, when it is determined in step S8 that the residual energy R _min is smaller than the threshold value W, the process proceeds to step S10, that is, the frequency analysis is terminated, but the residual energy is Even if R _min does not become smaller than the threshold value W, for example, the frequency analysis can be ended when the calculation of the residual energy R _min is repeated a predetermined number of times.

  FIG. 11 shows a configuration example of a decoding device 51 to which the present invention is applied, that is, a code string CD generated by the encoding device 31 of FIG. The decoding device 51 is further provided with an acoustic time-series signal generation unit (hereinafter abbreviated as a generation unit) 52 subsequent to the inverse amplitude operation unit 24 of the decoding device 2 of FIG. Other configurations are the same as those in FIG.

  The code sequence CD generated by the encoding device 31 supplied to the decoding device 51 is supplied to the code sequence decomposing unit 21.

  The code string decomposition unit 21 decomposes the input code string CD into spectrum information QF, quantization information Q, normalization information N, amplitude operation information G, and waveform information E, and also includes spectrum information QF and quantization information. Q and normalization information N are supplied to the inverse quantization / inverse normalization unit 22, amplitude operation information G is supplied to the inverse amplitude operation unit 24, and waveform information E is supplied to the generation unit 52. That is, for example, the waveform information E generated by the encoding device 31 (the frequency analysis unit 41 (FIG. 5) of the generation unit 32) for generating the low frequency component time series signal ES shown in FIG. 9A is generated by the generation unit. 52.

  The inverse quantization / inverse normalization unit 22 inversely quantizes the spectrum information QF input from the code string decomposition unit 21 based on the quantization information Q, and further denormalizes based on the normalization information N, The spectrum F ′ obtained as a result is output to the inverse spectrum converter 23.

  The inverse spectrum conversion unit 23 performs inverse spectrum conversion of the spectrum F ′ from the inverse quantization / inverse normalization unit 22 into a time series signal. That is, as a result, for example, a time-series signal GS ′ corresponding to the time-series signal GS shown in FIG. 9C generated by the encoding device 31 (amplitude operation unit 11) is generated.

  The inverse spectrum conversion unit 23 outputs the generated time series signal GS ′ to the inverse amplitude operation unit 24.

  The inverse amplitude operation unit 24 performs an amplitude operation on the time-series signal GS ′ from the inverse spectrum conversion unit 23 based on the amplitude operation information G from the code string decomposition unit 21, that is, the encoding device 31 (amplitude operation unit 11). In contrast to the amplitude operation performed in step 1, the amplitude operation in which the amplitude is operated is performed. As a result, for example, a residual time series signal RS ′ corresponding to the residual time series signal RS shown in FIG. 9B generated by the encoding device 31 (generation unit 32) is generated.

  The inverse amplitude operation unit 24 outputs the generated residual time series signal RS ′ to the generation unit 52.

  For example, the generation unit 52 is configured as shown in FIG. 12, and the waveform information E from the code string decomposition unit 21 is input to a low frequency component time-series signal generation unit (hereinafter abbreviated as a generation unit) 61. The residual time series signal RS ′ from the inverse amplitude operation unit 24 is supplied to the adder 62.

  Based on the input waveform information E, the generation unit 61 generates a low frequency component corresponding to the low frequency component time series signal ES generated by the encoding device 31 (the generation unit 42 of the generation unit 32 (FIG. 5)). A series signal ES ′ is generated and output to the adder 62.

  The adder 62 adds the low frequency component time series signal ES ′ from the generation unit 61 and the residual time series signal RS ′ from the inverse amplitude operation unit 24. That is, as a result, for example, an acoustic time series signal SS ′ corresponding to the acoustic time series signal SS shown in FIG. 7A input to the encoding device 31 is generated.

  The adder 62 outputs the generated acoustic time series signal SS ′ to an external device.

  Incidentally, in the encoding device 31 (FIG. 4) described above, the waveform information E is encoded by the code string generation unit 14, but the waveform information E may be encoded by normalization and quantization. it can. However, when the waveform information E is normalized and quantized and encoded, quantized waveform information including a quantization error (hereinafter referred to as waveform information QE) is supplied to the decoding device 51 (FIG. 11). It will be. That is, since the decoding device 51 generates the low frequency component time series signal ES ′ based on the waveform information QE, the low frequency component time series signal ES ′ is generated by the quantization error included in the waveform information QE. This is different from the low-frequency component time series signal ES generated by the encoding device 31. That is, in this case, the acoustic time-series signal SS ′ equivalent to the acoustic time-series signal SS cannot be decoded, and a hearing problem may occur.

  Therefore, even if the waveform information E is quantized and encoded by configuring the encoding device 31 as shown in FIG. 13 and the decoding device 51 as shown in FIG. The acoustic time series signal SS ′ can be generated.

  The encoding device 31 in FIG. 13 is provided with a residual time series signal generation unit (hereinafter abbreviated as a generation unit) 71 instead of the generation unit 32 of the encoding device 31 in FIG. Other configurations are the same as those in FIG.

  The generation unit 71 is configured as shown in FIG. 14, for example. That is, a normalization / quantization unit 81 and an inverse quantization / inverse normalization unit 82 are provided between the frequency analysis unit 41 and the generation unit 42 of the generation unit 32 in FIG.

  The normalization / quantization unit 81 normalizes and quantizes the waveform information E from the frequency analysis unit 41, and converts the waveform information QE obtained as a result thereof into an inverse quantization / inverse normalization unit 82 and a code string generation. To the unit 14.

  The inverse quantization / inverse normalization unit 82 inversely quantizes and inversely normalizes the waveform information QE from the normalization / quantization unit 81, and the waveform generated by the frequency analysis unit 41 obtained as a result thereof. Waveform information E ′ corresponding to the information E is output to the generation unit 42. The waveform information E ′ includes a quantization error.

  The generation unit 42 generates a low frequency component time series signal ES based on the waveform information E ′ from the inverse quantization / inverse normalization unit 82 and outputs the low frequency component time series signal ES to the subtractor 43.

  The subtractor 43 subtracts the low frequency component time series signal ES (including the quantization error indirectly) from the generation unit 42 from the input acoustic time series signal SS to generate a residual time series signal RS, Output to the amplitude operation unit 11.

  The residual time series signal RS is subjected to amplitude manipulation, spectral conversion, normalization, and quantization, and spectral information QF is generated. The generated spectrum information QF is encoded together with the waveform information QE and the like, and is supplied to the decoding device 51.

  FIG. 15 shows a configuration example of a decoding device 51 that decodes the code string CD generated by the encoding device 31 of FIG. The decoding device 51 is provided with an acoustic time series signal generation unit (hereinafter abbreviated as a generation unit) 91 instead of the generation unit 52 of the decoding device 51 of FIG. The other parts are the same as in FIG.

  The code sequence decomposition unit 21 converts the input code sequence CD supplied from the encoding device 31 of FIG. 13 into spectral information QF, quantization information Q, normalization information N, amplitude operation information G, and waveform information QE. In addition, the spectral information QF, the quantization information Q, and the normalization information N are converted into the inverse quantization / inverse normalization unit 22, the amplitude operation information G, the inverse amplitude operation unit 24, and the waveform information QE. Are supplied to the generation unit 91.

  The spectrum information QF separated from the code string CD is subjected to inverse quantization, inverse normalization, inverse spectrum conversion, and inverse amplitude operation by the code string decomposition unit 21 to obtain a residual time series signal RS ′.

  The generation unit 91 inversely quantizes the waveform information QE from the code string decomposition unit 21 and inversely quantizes the waveform information E ′. Then, the generation unit 91 generates the low frequency component time series signal ES ′ based on the waveform information E ′, and adds it to the residual time series signal RS ′ to generate the acoustic time series signal SS ′. .

  Since the low frequency component time series signal ES ′ generated here is generated based on the waveform information E ′ in the encoding device 31, the low frequency component time series signal ES ′ is the same as that of the encoding device. be able to.

  That is, since the same low frequency component time series signal can be used in the encoding device and the decoding device, an appropriate acoustic time series signal SS ′ is generated.

  FIG. 16 shows a configuration example of the generation unit 91. The generation unit 91 is provided with an inverse quantization / inverse normalization unit 101 before the generation unit 61 of the generation unit 52 of FIG.

  The inverse quantization / inverse normalization unit 101 performs inverse quantization and inverse normalization on the waveform information QE from the code string decomposition unit 21, and corresponds to the waveform information E generated by the encoding device 31 obtained as a result. The waveform information E ′ is output to the generation unit 61.

  The generation unit 61 generates a low frequency component time series signal ES ′ based on the waveform information E ′ from the inverse quantization / inverse normalization unit 101.

In addition, in the encoding device 31 in FIG. 4 described above, when the acoustic time series signal SS as illustrated in FIG. 17A is input, the generation unit 32 performs time from the time t ₁ as illustrated in FIG. 17B, for example. The acoustic time-series signal SS input during T (from time t ₁ to time t ₂ ) is divided as one block (block A), and between time t ₂ and time T as shown in FIG. 17C. The acoustic time-series signal SS input from (time t ₂ to time t ₃ ) is classified as one block (block B). That is, the acoustic time series signal SS is divided so as not to overlap.

However, as described above, the processing target frequency f _p utilized to produce a low frequency component time-sequential signal ES is a finite number, i.e., since the pure sound waveform is also a finite number, divided so as not to overlap as described above Depending on the frequency analysis result for the acoustic time-series signal SS, the low-frequency component time-series signal ES that is discontinuous between adjacent blocks may be generated. In other words, the decoding device 51 may not generate an appropriate acoustic time series signal SS ′.

  Therefore, by configuring the encoding device 31 as shown in FIG. 18, for example, and the decoding device 51 as shown in FIG. 21, a more appropriate acoustic time series signal SS ′ is generated. be able to.

  18 is provided with an acoustic time-series signal generation unit (hereinafter abbreviated as a generation unit) 111 instead of the generation unit 32 of the encoding device 31 of FIG.

  The generation unit 111 is configured as shown in FIG. 19, for example. That is, in this generation unit 111, a waveform information holding unit 121 is provided between the frequency analysis unit 41 and the generation unit 42 of the generation unit 32 in FIG.

  In this case, the acoustic time-series signal SS is segmented into blocks by a segmenting unit (not shown) so that a part of the acoustic time-series signal SS overlaps.

For example, for the acoustic time series signal SS as shown in FIG. 20A, the acoustic time series signal SS input from time t ₁₁ to time T (from time t ₁₁ to time t ₁₃ ) is divided into blocks A, The acoustic time series signal SS input between time t ₁₂ and time T (from time t ₁₂ to time t ₁₄ ), which is an intermediate time between time t ₁₁ and time t ₁₃ , is divided into block B and time t ₁₂ and time acoustic time-series signal SS is input to a period from time t ₁₃ is the intermediate time of the time T (from time t ₁₃ to time t ₁₅₎ of the t ₁₄ is divided into blocks C.

  The frequency analysis unit 41 thus performs frequency analysis on the acoustic time series signal SS in the block divided so as to partially overlap, and generates waveform information E based on the analysis result, The data is sequentially output to the waveform information holding unit 121.

  The waveform information holding unit 121 stores the waveform information E from the frequency analysis unit 41 for three blocks, and outputs the blocks to the generation unit 42.

Specifically, when the waveform information E for one block is input from the frequency analysis unit 41, the waveform information holding unit 121 stores the waveform information E for three blocks stored until that time (hereinafter referred to as a waveform). of the three waveform information E stored in the information holding portion 121, most previously stored waveform information E, the waveform information E _1, the next stored waveform information E, the waveform information E ₂ and the most after the stored waveform information E, respectively referred to as a waveform information E _3), and outputs the generator 42.

The waveform information holding unit 121 deletes the waveform information E ₁ which has been held, the waveform information stored as the waveform information E _2, as the waveform information E _1, the waveform which has been stored as the waveform information E ₃ Information E is stored as waveform information E ₂ , and waveform information input from frequency analysis unit 41 is stored as waveform information E ₃ .

The waveform information holding unit 121 repeats the same operation every time the waveform information E is input from the frequency analysis unit 41. That is, the generation unit 42 is supplied with the waveform information E _{1 to} E ₃ generated from the acoustic time-series signals SS that partially overlap each other.

_First , the generation unit 42 generates, for example, the low-frequency component time series signals ES _{1 to} ES ₃ shown in FIGS. 20B to 20D based on each of the waveform information E _{1 to} E ₃ .

The generating unit 42, the generated low-frequency component time-sequential signal ES ₂ (FIG. 20C), overlap at low frequencies the time-series signal ES ₂ and a time axis, the low-frequency component time-sequential signal ES ₁ part (in FIG. 20B And the portion of the low frequency component time series signal ES ₃ that overlaps the low frequency time series signal ES ₂ on the time axis (the portion shown by the solid line in FIG. 20D). A low frequency time series signal ES as shown by a solid line in FIG. 20E is generated and output to the subtractor 43 by applying the window function W (t) shown in Equation (13) to the combined result. To do.

W (t) = 0.5 × (1−cos (2πt / L)) (13)

  The low-frequency component time series signal ES generated in this way does not become discontinuous between blocks.

  FIG. 21 shows a configuration example of a decoding device 51 that decodes the code string CD generated by the encoding device 31 of FIG.

  This decoding device is provided with an acoustic time-series signal generation unit (hereinafter abbreviated as a generation unit) 131 instead of the generation unit 52 of the decoding device 51 of FIG. The other parts are the same as those in FIG.

  The generation unit 131 is configured as shown in FIG. 22, for example. That is, the generation unit 131 is provided with a waveform information holding unit 141 before the generation unit 61 of FIG.

The waveform information holding unit 141 operates in the same manner as the waveform information holding unit 121 of the generation unit 111 of the encoding device 31, holds waveform information E _{1 to} E ₃ for three blocks, and outputs them to the generation unit 61. To do.

The generation unit 61 operates in the same manner as the generation unit 42 of the generation unit 111 of the encoding device 31, and based on the _three waveform information E _{1 to} E ₃ obtained from the waveform information holding unit 141, the low frequency component time series The signals ES _{1 to} ES ₃ are respectively generated, and the generated low frequency component time series signals ES _{1 to} ES ₃ are synthesized as described with reference to FIG. 20, and the window function W ( t), and the final low frequency component time series signal ES obtained as a result is output to the adder 62.

  Moreover, in the encoding apparatus 31 of FIG. 4 mentioned above, although the acoustic time series signal SS was encoded without carrying out a band division, coding efficiency can be improved more by carrying out a band division.

  Therefore, the encoding device 31 is configured as shown in FIG. 23 and the decoding device 51 is configured as shown in FIG. 24, for example, so that the acoustic time series signal SS is divided and encoded. Can do.

  23 includes a residual time series generation unit 32, amplitude operation units 11-1 to 11-4, spectrum conversion units 12-1 to 12-4, and normalization / quantization units 13-1 to 13-13. 4 and the code string generation unit 14, and the band division filter 151 provided in the preceding stage of the generation unit 32.

The band division filter 151 divides the input acoustic time series signal SS into four bands using, for example, PQF (Polyphase Quadrature Filter) or QMF (Quadrature Mirror Filter), and generates band signals FS _{1 to} FS _4. The band signal FS ₁ is generated in the generation unit 32, the band signal FS ₂ in the amplitude operation unit 11-2, the band signal FS ₃ in the amplitude operation unit 11-3, and the band signal FS ₄ in the amplitude operation unit. 11-4 respectively.

The generation unit 32, the amplitude operation units 11-1 to 11-4, the spectrum conversion units 12-1 to 12-4, the normalization / quantization units 13-1 to 13-4, and the code string generation unit 14 are illustrated in FIG. The amplitude operation unit 11-1 performs an amplitude operation on the residual time series signal RS from the generation unit 32, and the amplitude operation unit 11- 2 to 11-4 performs amplitude operation on the band signal FS ₂ to FS _4.

The code string generation unit 14 includes waveform information E from the generation unit 32, amplitude operation information G _{1 to} G ₄ from the amplitude operation units 11-1 to 11-4, and normalization / quantization units 13-1 to 13-13. -4, spectrum information QF _{1 to} QF ₄ , quantization information Q _{1 to} Q ₄ , and normalization information N _{1 to} N ₄ are respectively supplied. Generate a column.

  The decoding device 51 of FIG. 24 includes one code string decomposition unit 21, four inverse quantization / inverse normalization units 22-1 to 22-4, and four inverse spectrum transforms of the decoding device 51 of FIG. Sections 23-1 to 23-4, four inverse amplitude operation sections 24-1 to 24-4, one generation section 52, and one band synthesis filter 161.

The code string decomposing unit 21 converts the input code string CD into four pieces of spectrum information QF _{1 to} QF ₄ , four pieces of quantized information Q _{1 to} Q ₄ , four pieces of normalized information N _{1 to} N ₄ , And the amplitude operation information G _{1 to} G ₄ and one waveform information E, and the spectral information QF _{1 to} QF ₄ , the quantization information Q _{1 to} Q ₄ , and the normalization information N _{1 to} N ₄ are inverted. the quantization / inverse normalization unit 22-1 to 22-4, four amplitude operation information G ₁ to G _4, on the contrary the amplitude operation unit 24-1 through 24-4, and the waveform information E, generator The data is output to 52 respectively.

The inverse quantization / inverse normalization units 22-1 to 22-4, the inverse spectrum conversion units 23-1 to 23-4, the inverse amplitude operation units 24-1 to 24-4, and the generation unit 52 are shown in FIG. However, although the detailed description thereof is omitted, the generation unit 52 generates the acoustic time-series signal SS ′, and the inverse amplitude operation units 24-2 to 24-4 perform the time-series signal GS ₂ ′ to GS. ₄ ′ (respectively signals similar to the band signals FS _{2 to} FS ₄ in the encoding device 31) are output to the band synthesis filter 161, respectively.

  The band synthesis filter 161 synthesizes using, for example, IPQF (Inverse Polyphase Quadrature Filter) or IQMF (Inverse Quadrature Filter), generates a final acoustic time series signal SS ′, and outputs it to an external device.

As described above, a specific band signal (for example, the band signal FS ₁ in the above-described embodiment) is processed by the generation unit 32 of the encoding device 31 so that the amplitude operation is performed. The band signals (for example, band signals FS _{2 to} FS ₄ ) can be encoded as in the prior art, and the acoustic time series signal SS can be efficiently encoded.

  The present invention can be applied to an audio recording / reproducing apparatus.

  The series of processes described above can be realized by hardware, but can also be realized by software. When the series of processing is realized by software, a program constituting the software is installed in a computer, and the program is executed by the computer, whereby the above-described encoding device 31 and decoding device 51 are functional. To be realized.

  FIG. 25 is a block diagram illustrating a configuration of an embodiment of a computer 501 that functions as the encoding device 31 and the decoding device 51 as described above. An input / output interface 516 is connected to a CPU (Central Processing Unit) 511 via a bus 515, and the CPU 511 receives a command from an input unit 518 such as a keyboard and a mouse via the input / output interface 516. When input, it is stored in a recording medium such as a ROM (Read Only Memory) 512, a hard disk 514, or a magnetic disk 531, an optical disk 532, a magneto-optical disk 533, or a semiconductor memory 534 mounted on the drive 520 The program is loaded into a RAM (Random Access Memory) 513 and executed. Thereby, the various processes described above are performed. Further, the CPU 511 outputs the processing result to a display unit 517 such as an LCD (Liquid Crystal Display) via the input / output interface 516 as necessary. The program is stored in advance in the hard disk 514 or ROM 512 and provided to the user integrally with the computer 501 or as a package medium such as the magnetic disk 531, the optical disk 532, the magneto-optical disk 533, and the semiconductor memory 534. Or can be provided to the hard disk 514 via the communication unit 519 from a satellite, a network, or the like.

  In the present specification, the step of describing the program provided by the recording medium is not limited to the processing performed in chronological order according to the described order, but is not necessarily performed in chronological order. It also includes processes that are executed individually.

It is a block diagram which shows the structural example of the conventional encoding apparatus and decoding apparatus. It is a figure explaining amplitude operation. It is a figure explaining operation | movement of the conventional encoding apparatus and decoding apparatus. It is a block diagram which shows the structural example of the encoding apparatus to which this invention is applied. FIG. 5 is a block diagram illustrating a configuration example of a low frequency component time series signal generation unit in FIG. 4. It is a flowchart explaining operation | movement of the low frequency component time series signal generation part of FIG. It is a figure explaining the process of step S2 of FIG. 6 is a diagram showing an example of waveform information E. FIG. It is a figure explaining operation | movement of the encoding apparatus to which this invention is applied. 6 is a diagram showing another example of waveform information E. FIG. It is a block diagram which shows the structural example of the decoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of the acoustic time series signal generation part of FIG. It is a block diagram which shows the other structural example of the encoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of the residual time series signal generation part of FIG. It is a block diagram which shows the other structural example of the decoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of the acoustic time series signal generation part of FIG. It is a figure explaining operation | movement of the encoding apparatus of FIG. It is a block diagram which shows the other structural example of the encoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of the residual time series signal generation part of FIG. It is a figure explaining operation | movement of the encoding apparatus of FIG. It is a block diagram which shows the other structural example of the decoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of the acoustic time series signal generation part of FIG. It is a block diagram which shows the other structural example of the encoding apparatus to which this invention is applied. It is a block diagram which shows the other structural example of the decoding apparatus to which this invention is applied. It is a block diagram which shows the structural example of a computer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Amplitude operation part, 12 Spectrum conversion part, 13 Normalization / quantization part, 14 Code stream generation part, 21 Code stream decomposition part, 22 Inverse quantization / inverse normalization part, 23 Inverse spectrum conversion part, 24 Inverse amplitude operation Unit, 31 encoding device, 32 residual time series signal generation unit, 41 frequency analysis unit, 42 low frequency component time series signal generation unit, 43 subtractor, 51 decoding device, 52 acoustic time series signal generation unit, 61 low frequency Component time series signal generation unit, 62 adder, 71 residual time series signal generation unit, 81 normalization / quantization unit, 82 inverse quantization / inverse normalization unit, 91 acoustic time series signal generation unit, 101 inverse quantization / Denormalization unit, 111 residual time series signal generation unit, 121 waveform information holding unit, 131 acoustic time series signal generation unit, 141 waveform information holding unit, 151 bands Split filter, 161 band synthesis filter

Claims (10)

Classification means for dividing the input time series signal into blocks of a predetermined length;
Waveform information generating means for performing a predetermined frequency analysis on the input time series signal in the block and generating waveform information based on the analysis result;
A residual signal generating means for generating a residual signal by removing a signal based on the waveform information from the input time series signal in the block;
An amplitude operation means for analyzing the amplitude of the residual signal, performing a predetermined amplitude operation on the residual signal according to predetermined amplitude operation information based on the analysis result, and generating a quantization target signal;
Quantization means for generating a quantized signal by quantizing the quantization target signal;
An encoding apparatus, comprising: code string generation means for encoding the waveform information, the amplitude operation information, and the quantized signal to generate a code string. In an encoding device that divides an input time-series signal into M band signals and divides the band signals into predetermined blocks and encodes them,
Waveform information generating means for performing a predetermined frequency analysis on a signal in a block of at least one band signal and generating waveform information based on the analysis result;
A residual signal generating means for generating a residual signal by removing a signal based on the waveform information from the band signal;
An amplitude operation means for analyzing the amplitude of the residual signal and performing a predetermined amplitude operation on the residual signal according to predetermined amplitude operation information based on the analysis result to generate a quantization target signal. An encoding apparatus characterized by that. Classification means for dividing the input time series signal into blocks of a predetermined length;
Waveform information generating means for performing a predetermined frequency analysis on the input time series signal in the block and generating waveform information based on the analysis result;
A residual signal generating means for generating a residual signal by removing a signal based on the waveform information from the input time series signal in the block;
Quantization means for converting the residual signal into a frequency component and quantizing the quantized signal to generate a quantized signal;
A coding apparatus comprising: a code string generation unit that codes the waveform information and the quantized signal to generate a code string. A step of dividing the input time-series signal into blocks of a predetermined length;
A waveform information generation step for performing a predetermined frequency analysis on the input time-series signal in the block and generating waveform information based on the analysis result;
A residual signal generating step of generating a residual signal by removing a signal based on the waveform information from the input time-series signal in the block;
An amplitude operation step of analyzing the amplitude of the residual signal, performing a predetermined amplitude operation on the residual signal according to predetermined amplitude operation information based on the analysis result, and generating a quantization target signal;
A quantization step of quantizing the quantization target signal to generate a quantized signal;
And a code string generating step of generating a code string by encoding the waveform information, the amplitude operation information, and the quantized signal. A step of dividing the input time-series signal into blocks of a predetermined length;
A waveform signal generation step for performing a predetermined frequency analysis on the input time-series signal in the block and generating waveform information based on the analysis result;
A residual signal generating step of generating a residual signal by removing a signal based on the waveform information from the input time-series signal in the block;
An amplitude operation step of analyzing the amplitude of the residual signal, performing a predetermined amplitude operation on the residual signal according to predetermined amplitude operation information based on the analysis result, and generating a quantization target signal;
A quantization step of quantizing the quantization target signal to generate a quantized signal;
A code string generation step of generating a code string by encoding the waveform information, the amplitude operation information, and the quantized signal. A recording medium on which a computer-readable program is recorded. In a decoding device that receives and decodes a code string generated by encoding a time-series signal for each block,
Decomposition means for decomposing the code string into waveform information, amplitude operation information, and a quantized signal;
An inverse quantization means for inversely quantizing the quantized signal;
Inverse amplitude operation means for performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information on the inversely quantized signal, and generating an amplitude-operated signal;
A decoding apparatus comprising: a time-series signal generating unit that generates a time-series signal based on the signal generated according to the waveform information and the amplitude-controlled signal. In a decoding device that receives and decodes a code string generated by encoding at least one band signal among time-series signals divided into M band signals,
Decomposition means for decomposing the code string into waveform information, amplitude operation information, and a quantized signal;
An inverse quantization means for inversely quantizing the quantized signal;
Inverse amplitude operation means for performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information on the inversely quantized signal, and generating an amplitude-operated signal;
A decoding apparatus comprising: a time-series signal generating unit that generates a time-series signal based on the signal generated according to the waveform information and the amplitude-controlled signal. In a decoding device that receives and decodes a code string generated by encoding a time-series signal,
Decomposition means for decomposing the code string into waveform information and a quantized signal;
Inverse frequency conversion means for performing inverse frequency conversion by inverse quantization of the quantized signal;
A decoding apparatus comprising: time-series signal generation means for generating a time-series signal based on the signal generated according to the waveform information and the signal subjected to the inverse frequency conversion. In a decoding method for receiving and decoding a code string generated by encoding a time-series signal for each block,
A decomposition step of decomposing the code string into waveform information, amplitude manipulation information, and a quantized signal;
An inverse quantization step for inversely quantizing the quantized signal;
An inverse amplitude operation step for generating an amplitude-controlled signal by performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information with respect to the inversely quantized signal;
A decoding method comprising: a time-series signal generation step of generating a time-series signal based on the signal generated according to the waveform information and the amplitude-controlled signal. A program for a decoding apparatus that receives and decodes a code string generated by encoding a time-series signal for each block,
A decomposition step of decomposing the code string into waveform information, amplitude manipulation information, and a quantized signal;
An inverse quantization step for inversely quantizing the quantized signal;
An inverse amplitude operation step for generating an amplitude-controlled signal by performing an amplitude operation opposite to that at the time of encoding according to the amplitude operation information with respect to the inversely quantized signal;
A time-series signal generating step for generating a time-series signal corresponding to the encoded time-series signal based on the signal generated according to the waveform information and the amplitude-controlled signal. Is a recording medium on which a readable program is recorded.

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