Audio signal processing apparatus

Claim 2

An audio signal encoding apparatus comprising: first means for implementing matrix operation between a first audio signal and a second audio signal to generate a first channel signal and a second channel signal correlating with each other, the first audio signal and the second audio signal relating to a same sampling frequency; a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; fourth means provided in the lossless encoder for selecting one from first different linear prediction methods and predictively encoding the first channel signal according to the selected one of the first different linear prediction methods, wherein the first different linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; fifth means provided in the lossless encoder for selecting one from second different linear prediction methods and predictively encoding the second channel signal according to the selected one of the second different linear prediction methods, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and sixth means provided in the lossless encoder for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means.

Claim 3

An audio signal encoding apparatus as recited in claim 1 , wherein the signal of the predetermined format which is generated by the sixth means contains the first sample selected by the second means for every frame, the first sample selected by the third means for every frame, the smallest first prediction-error signal generated by the fourth means for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the fifth means for each of sub frames composing one frame.

Claim 4

An audio signal encoding apparatus as recited in claim 1 , further comprising seventh means provided in the lossless encoder for generating a variable-bit-rate bit stream data in response to the smallest first prediction-error signal generated by the fourth means and the smallest second prediction-error signal generated by the fifth means.

Claim 5

An audio signal decoding apparatus for decoding an input audio signal into first and second original audio signals, wherein the input audio signal has been generated by an audio signal encoding apparatus comprising 1) first means for implementing matrix operation between a first audio signal and a second audio signal to generate a first channel signal and a second channel signal correlating with each other, the first audio signal and the second audio signal relating to a same sampling frequency; 2) a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding resultant signal from which a decoding apparatus can reproduce the first audio signal and the second audio signal: 3) second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; 4) third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; 5) fourth means provided in the lossless encoder for selecting one from first different linear prediction methods and predictively encoding the first channel signal according to the selected one of the first different linear prediction methods, wherein the first different linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; 6) fifth means provided in the lossless encoder for selecting one from second different linear prediction methods and predictively encoding the second channel signal according to the selected one of the second different linear prediction methods, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and 7) sixth means provided in the lossless encoder for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means; the audio signal decoding apparatus comprising: a lossless decoder subjecting the input audio signal to lossless decoding to reproduce original audio information therefrom: extracting means provided in the lossless decoder for extracting the smallest first prediction-error signal and the smallest second prediction-error signal from the input audio signal; calculating means provided in the lossless decoder for calculating a prediction value of the first channel signal and a prediction value of the second channel signal from the smallest first prediction-error signal and the smallest second prediction-error signal extracted by the extracting means; and reproducing means for reproducing the first audio signal and the second audio signal from the prediction values calculated by the calculating means.

Claim 6

An audio signal decoding apparatus for decoding an input audio signal into first and second original audio signals, wherein the input audio signal has been generated by an audio signal encoding apparatus comprising 1) first means for implementing matrix operation between a first audio signal and a second audio signal to generate a first channel signal and a second channel signal correlating with each other, the first audio signal and the second audio signal relating to a same sampling frequency; 2) a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding resultant signal from which a decoding apparatus can reproduce the first audio signal and the second audio signal: 3) second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; 4) third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; 5) fourth means provided in the lossless encoder for selecting one from first different linear prediction methods and predictively encoding the first channel signal according to the selected one of the first different linear prediction methods, wherein the first different linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; 6) fifth means provided in the lossless encoder for selecting one from second different linear prediction methods and predictively encoding the second channel signal according to the selected one of the second different linear prediction methods, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and 7) sixth means provided in the lossless encoder for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means; the audio signal decoding apparatus comprising: a lossless decoder subjecting the input audio signal to lossless decoding to reproduce original audio information therefrom: extracting means provided in the lossless decoder for extracting the smallest first prediction-error signal and the smallest second prediction-error signal from the input audio signal; calculating means provided in the lossless decoder for calculating a prediction value of the first channel signal and a prediction value of the second channel signal from the smallest first prediction-error signal and the smallest second prediction-error signal extracted by the extracting means; and reproducing means for reproducing the first audio signal and the second audio signal from the prediction values calculated by the calculating means.

Claim 7

An audio signal decoding apparatus as recited in claim 4 , wherein the signal of the predetermined format which is generated by the sixth means contains the first sample selected by the second means for every frame, the first sample selected by the third means for every frame, the smallest first prediction-error signal generated by the fourth means for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the fifth means for each of sub frames composing one frame.

Claim 10

A method as recited in claim 6 , wherein the signal of the predetermined format which is generated by the step 5) contains the first sample selected by the step 1) for every frame, the first sample selected by the step 2) for every frame, the smallest first prediction-error signal generated by the step 3) for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the step 4) for each of sub frames composing one frame.

Claim 11

A recording medium storing a signal of a predetermined format having a header information area and a user data area, the user data area being loaded with a signal resulting from lossless data compression, the lossless data compression including the steps of 1) implementing matrix operation between a first audio signal and a second audio signal to generate a first channel signal and a second channel signal correlating with each other, the first audio signal and the second audio signal relating to a same sampling frequency; and 2) subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: wherein the subjecting step comprises 2a) selecting a first sample among samples of the first channel signal for every prescribed interval; 2b) selecting a first sample among samples of the second channel signal for every prescribed interval; 2c) selecting one from first different linear prediction methods and predictively encoding the first channel signal according to the selected one of the first different linear prediction methods, wherein the first different linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the selected first linear prediction method generates a smallest of the first prediction-error signals; 2d) electing one from second different linear prediction methods and predictively encoding the second channel signal according to the selected one of the second different linear prediction methods, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the selected second linear prediction method generates a smallest of the second prediction-error signals; and 2e) loading the user data area with the selected first sample of the first channel signal, the selected first sample of the second channel signal, the smallest first prediction-error signal generated by the selected first linear prediction method, the smallest second prediction-error signal generated by the selected second linear prediction method, an information piece representing the selected first linear prediction method, and an information piece representing the selected second linear prediction method.

Claim 12

A recording medium storing a signal of a predetermined format having a header information area and a user data area, the user data area being loaded with a signal resulting from lossless data compression, the lossless data compression including the steps of 1) implementing matrix operation between a first audio signal and a second audio signal to generate a first channel signal and a second channel signal correlating with each other, the first audio signal and the second audio signal relating to a same sampling frequency; and 2) subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: wherein the subjecting step comprises 2a) selecting a first sample among samples of the first channel signal for every prescribed interval; 2b) selecting a first sample among samples of the second channel signal for every prescribed interval; 2c) selecting one from first different linear prediction methods and predictively encoding the first channel signal according to the selected one of the first different linear prediction methods, wherein the first different linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the selected first linear prediction method generates a smallest of the first prediction-error signals; 2d) electing one from second different linear prediction methods and predictively encoding the second channel signal according to the selected one of the second different linear prediction methods, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the selected second linear prediction method generates a smallest of the second prediction-error signals; and 2e) loading the user data area with the selected first sample of the first channel signal, the selected first sample of the second channel signal, the smallest first prediction-error signal generated by the selected first linear prediction method, the smallest second prediction-error signal generated by the selected second linear prediction method, an information piece representing the selected first linear prediction method, and an information piece representing the selected second linear prediction method.

Claim 13

A recording medium as recited in claim 8 , wherein the signal of the predetermined format contains the selected first sample of the first channel signal for every frame, the selected first sample of the second channel signal for every frame, the smallest first prediction-error signal generated by the selected first linear prediction method for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the selected second linear prediction method for each of sub frames composing one frame.

Claim 16

A method as recited in claim 10 , wherein the signal of the predetermined format which is generated by the step 5) contains the first sample selected by the step 1) for every frame, the first sample selected by the step 2) for every frame, the smallest first prediction-error signal generated by the step 3) for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the step 4) for each of sub frames composing one frame.

Claim 17

An audio signal encoding apparatus comprising: first means for implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; fourth means provided in the lossless encoder for selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; fifth means provided in the lossless encoder for selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction methods, wherein the second linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and sixth means provided in the lossless encoder for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means.

Claim 18

An audio signal encoding apparatus comprising: first means for implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; fourth means provided in the lossless encoder for selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; fifth means provided in the lossless encoder for selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction methods, wherein the second linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and sixth means provided in the lossless encoder for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means.

Claim 19

An audio signal encoding apparatus as recited in claim 12 , wherein the signal of the predetermined format which is generated by the sixth means contains the first sample selected by the second means for every frame, the first sample selected by the third means for every frame, the smallest first prediction-error signal generated by the fourth means for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the fifth means for each of sub frames composing one frame.

Claim 20

An audio signal encoding apparatus as recited in claim 12 , further comprising seventh means provided in the lossless encoder for generating a variable-bit-rate bit stream data in response to the smallest first prediction-error signal generated by the fourth means and the smallest second prediction-error signal generated by the fifth means.

Claim 21

An audio signal decoding apparatus for decoding an input audio signal into first and second original audio signals, wherein the input audio signal has been generated by an audio signal encoding apparatus comprising 1) first means for implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; 2) a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding apparatus can reproduce the first audio signal and the second audio signal: 3) second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; 4) fourth means provided in the lossless encoder for selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; 6) fifth means provided in the lossless encoder for selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction method, wherein the second linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and 7) sixth means for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means; the audio signal decoding apparatus comprising: a lossless decoder subjecting the input audio signal to lossless decoding to reproduce original audio information therefrom: extracting means provided in the lossless decoder for extracting the smallest first prediction-error signal and the smallest second prediction-error signal from the input audio signal; calculating means provided in the lossless decoder for calculating a prediction value of the first channel signal and a prediction value of the second channel signal from the smallest first prediction-error signal and the smallest second prediction-error signal extracted by the extracting means; and reproducing means for reproducing the first audio signal and the second audio signal from the prediction values calculated by the calculating means.

Claim 22

An audio signal decoding apparatus for decoding an input audio signal into first and second original audio signals, wherein the input audio signal has been generated by an audio signal encoding apparatus comprising 1) first means for implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; 2) a lossless encoder subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding apparatus can reproduce the first audio signal and the second audio signal: 3) second means provided in the lossless encoder for selecting a first sample among samples of the first channel signal for every prescribed interval; third means provided in the lossless encoder for selecting a first sample among samples of the second channel signal for every prescribed interval; 4) fourth means provided in the lossless encoder for selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the first linear prediction method selected by the fourth means generates a smallest of the first prediction-error signals; 6) fifth means provided in the lossless encoder for selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction method, wherein the second linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the second linear prediction method selected by the fifth means generates a smallest of the second prediction-error signals; and 7) sixth means for generating a signal of a predetermined format having a header information area and a user data area, and loading the user data area with the first sample selected by the second means, the first sample selected by the third means, the smallest first prediction-error signal generated by the fourth means, the smallest second prediction-error signal generated by the fifth means, an information piece representing the first linear prediction method selected by the fourth means, and an information piece representing the second linear prediction method selected by the fifth means; the audio signal decoding apparatus comprising: a lossless decoder subjecting the input audio signal to lossless decoding to reproduce original audio information therefrom: extracting means provided in the lossless decoder for extracting the smallest first prediction-error signal and the smallest second prediction-error signal from the input audio signal; calculating means provided in the lossless decoder for calculating a prediction value of the first channel signal and a prediction value of the second channel signal from the smallest first prediction-error signal and the smallest second prediction-error signal extracted by the extracting means; and reproducing means for reproducing the first audio signal and the second audio signal from the prediction values calculated by the calculating means.

Claim 23

An audio signal decoding apparatus as recited in claim 15 , wherein the signal of the predetermined format which is generated by the sixth means contains the first sample selected by the second means for every frame, the first sample selected by the third means for every frame, the smallest first prediction-error signal generated by the fourth means for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the fifth means for each of sub frames composing one frame.

Claim 26

A method as recited in claim 17 , wherein the signal of the predetermined format which is generated by the step 5) contains the first sample selected by the step 1) for every frame, the first sample selected by the step 2) for every frame, the smallest first prediction-error signal generated by the step 3) for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the step 4) for each of sub frames composing one frame.

Claim 27

A recording medium storing a signal of a predetermined format having a header information area and a user data area, the user data area being loaded with a signal resulting from lossless data compression, the lossless data compression including the steps of 1) implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; and 2) subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: wherein the subjecting step comprises 2a) selecting a first sample among samples of the first channel signal for every prescribed interval; 2b) selecting a first sample among samples of the second channel signal for every prescribed interval; 2c) selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the selected first linear prediction method generates a smallest of the first prediction-error signals; 2d) selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction method, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the selected second linear prediction method generates a smallest of the second prediction-error signals; and 2e) loading the user data area with the selected first sample of the first channel signal, the selected first sample of the second channel signal, the smallest first prediction-error signal generated by the selected first linear prediction method, the smallest second prediction-error signal generated by the selected second linear prediction method, an information piece representing the selected first linear prediction method, and an information piece representing the selected second linear prediction method.

Claim 28

A recording medium storing a signal of a predetermined format having a header information area and a user data area, the user data area being loaded with a signal resulting from lossless data compression, the lossless data compression including the steps of 1) implementing matrix operation between a first audio signal and a second audio signal selected from at least three audio signals composing a multi-channel audio signal to generate a first channel signal and a second channel signal correlating with each other; and 2) subjecting the first channel signal and the second channel signal to lossless encoding to convert the first channel signal and the second channel signal into an encoding-resultant signal from which a decoding side can reproduce the first audio signal and the second audio signal: wherein the subjecting step comprises 2a) selecting a first sample among samples of the first channel signal for every prescribed interval; 2b) selecting a first sample among samples of the second channel signal for every prescribed interval; 2c) selecting one from first linear prediction methods different from each other in characteristics and predictively encoding the first channel signal according to the selected first linear prediction method, wherein the first linear prediction methods are of predicting the first channel signal from a past condition of the first channel signal to generate first different prediction signals for the first channel signal, and generating first prediction-error signals representing differences between the first channel signal and the first different prediction signals respectively, and wherein the selected first linear prediction method generates a smallest of the first prediction-error signals; 2d) selecting one from second linear prediction methods different from each other in characteristics and predictively encoding the second channel signal according to the selected second linear prediction method, wherein the second different linear prediction methods are of predicting the second channel signal from a past condition of the second channel signal to generate second different prediction signals for the second channel signal, and generating second prediction-error signals representing differences between the second channel signal and the second different prediction signals respectively, and wherein the selected second linear prediction method generates a smallest of the second prediction-error signals; and 2e) loading the user data area with the selected first sample of the first channel signal, the selected first sample of the second channel signal, the smallest first prediction-error signal generated by the selected first linear prediction method, the smallest second prediction-error signal generated by the selected second linear prediction method, an information piece representing the selected first linear prediction method, and an information piece representing the selected second linear prediction method.

Claim 29

A recording medium as recited in claim 19 , wherein the signal of the predetermined format contains the selected first sample of the first channel signal for every frame, the selected first sample of the second channel signal for every frame, the smallest first prediction-error signal generated by the selected first linear prediction method for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the selected second linear prediction method for each of sub frames composing one frame.

Claim 32

A method as recited in claim 21 , wherein the signal of the predetermined format which is generated by the step 5) contains the first sample selected by the step 1) for every frame, the first sample selected by the step 2) for every frame, the smallest first prediction-error signal generated by the step 3) for each of sub frames composing one frame, and the smallest second prediction-error signal generated by the step 4) for each of sub frames composing one frame.