Audio signal processing apparatus

1. An audio signal encoding method comprising the steps of:

quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number;

implementing matrix operation among the first multiple-channel digital audio signals, to generate second multiple-channel audio signals correlating with each other;

compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; and

formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate.

2. An audio signal encoding method as recited in claim 1 , further comprising the step of:

formatting the packet header to include a decoding time stamp (DTS) to be used as decoding timing at which the access unit be read out from an input buffer in a decoder side.

3. An audio signal decoding method for decoding an input audio signal into original multiple-channel digital audio signals, wherein the input audio signal has been generated by an audio signal encoding method comprising the steps of a) quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number; b) implementing matrix operation among the first multiple-channel digital audio signals to generate second multiple-channel audio signals correlating with each other; c) compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; and d) formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate; the audio signal decoding method comprising the steps of:

separating an audio pack into an access unit composed of a sub packet and a sync information portion, where said access unit is of variable length;

extracting compression-resultant multiple-channel signals from the sub packet of the access unit;

expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively, where said compression-resultant multiple-channel signals are compressed with a variable bit rate;

extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and

converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.

4. An audio signal decoding method for decoding an input audio signal into original multiple-channel digital audio signals, wherein the input audio signal has been generated by an audio signal encoding method comprising the steps of a) quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number; b) implementing matrix operation among the first multiple-channel digital audio signals to generate second multiple-channel audio signals correlating with each other; c) compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; d) formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate; and 5) formatting the packet header to include a decoding time stamp (DTS) to be used as decoding timing at which the access unit be read out from an input buffer in a decoder side, the audio signal decoding method comprising the steps of:

extracting a decoding time stamp (DTS) from the packet header; separating an audio pack into an access unit composed of a sub packet and a sync information portion, where said access unit is of variable length;

reading out the access unit from an input buffer at the timing of the decoding time stamp (DTS) extracted from the packet header;

extracting compression-resultant multiple-channel signals from the sub packet of the access unit;

expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively, where said compression-resultant multiple-channel signals are compressed with a variable bit rate;

extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and

converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.

5. A method of receiving and decoding for receiving and decoding an input audio signal into original multiple-channel digital audio signals, wherein the input audio signal has been generated by an audio signal encoding method comprising the steps of a) quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number; b) implementing matrix operation among the first multiple-channel digital audio signals to generate second multiple-channel audio signals correlating with each other; c) compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; and d) formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate; the method comprising the steps of:

receiving an audio pack through a communication line;

separating the audio pack into an access unit composed of a sub packet and a sync information portion, where said access unit is of variable length;

extracting compression-resultant multiple-channel signals from the sub packet of the access unit;

expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively, where said compression-resultant multiple-channel signals are compressed with a variable bit rate;

extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and

converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.

6. A method of receiving and decoding for receiving and decoding an input audio signal into original multiple-channel digital audio signals, wherein the input audio signal has been generated by an audio signal encoding method comprising the steps of a) quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number; b) implementing matrix operation among the first multiple-channel digital audio signals to generate second multiple-channel audio signals correlating with each other; c) compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; d) formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate; and 5)formatting the packet header to include a decoding time stamp (DTS) to be used as decoding timing at which the access unit be read out from an input buffer in a decoder side, the method comprising the steps of:

receiving an audio pack including a packet through a communication line;

extracting a decoding time stamp (DTS) from a packet header of the packet;

separating the audio pack into an access unit composed of a sub packet and a sync information portion, where said access unit is of variable length;

reading out the access unit from an input buffer at the timing of the decoding time stamp (DTS) extracted from the packet header;

extracting compression-resultant multiple-channel signals from the sub packet of the access unit;

expanding the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively, where said compression-resultant multiple-channel signals are compressed with a variable bit rate;

extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion; and

converting the multiple-channel digital audio signals into analog audio signals in response to the signal representative of the sampling frequency and the signal representative of the quantization bit number.

7. A transmission medium for transmitting a formatting-resultant signal which is decoded by an audio signal decoding apparatus for decoding an input audio signal into original multiple-channel digital audio signals, wherein the input audio signal has been generated by an audio signal encoding apparatus comprising a) means for quantizing first multiple-channel analog audio signals into corresponding first multiple-channel digital audio signals at a sampling frequency and a quantization bit number; b) means for implementing matrix operation among the first multiple-channel digital audio signals to generate second multiple-channel audio signals correlating with each other; c) means for compressing the second multiple-channel audio signals into compression-resultant multiple-channel signals respectively, the compression-resultant multiple-channel signals relating to a smallest prediction-error lossless compression; and d) means for formatting the compression-resultant multiple-channel signals into a formatting-resultant signal of an audio pack including a pack header and a packet, the packet containing a packet header and an access unit composed of a sub packet and a sync information portion, the sub packet containing at least portions of the compression-resultant multiple-channel signals, the sync information portion containing the signal representative of the sampling frequency and the signal representative of the quantization bit number, where said access unit is of variable length and said compression-resultant multiple-channel signals are compressed with a variable bit rate; the transmission medium comprising:

means for separating a formatting-resultant signal into an access unit composed of a sub packet and a sync information portion, where said access unit is of variable length;

means for extracting the extracted compression-resultant multiple-channel signals into multiple-channel digital audio signals respectively, where said compression-resultant multiple-channel signal are compressed with a variable bit rate; and

means for extracting a signal representative of a sampling frequency and a signal representative of a quantization bit number from the sync information portion.