Differential stereo using two coding techniques

A coding device for coding signals, comprising:

• first signal generating means for generating a first audio signal from a stereo channel included in a plurality of input channels, wherein the stereo channel corresponds to a right channel having an acoustic signal and a left channel having another acoustic signal;
• second signal generating means for determining a signal level corresponding to one of the right and left channels and another signal level from the other of the right and left channels, and for selecting a second audio signal on the basis of the signal levels, such that the second audio signal is selected from the group consisting of the right channel, the left channel, and a signal generated by subtracting the right channel from the left channel that is different than the first audio signal;
• and
• coding means for coding the first audio signal, the selected second audio signal, and a signal that indicates the selection of the second audio signal, wherein coding the first audio signal is done via a first coding technique, and coding the selected second audio signal is done via a second coding technique which is different from said first coding technique.

A decoding method for decoding coded signals, comprising the steps of:

• separating from a code string a first coded signal, a second coded signal, and constituent information indicating a constituent state of a channel signal constitution the second coded signal;
• decoding the separated first and second coded signals, respectively, to generate first and second signals, wherein decoding the separated first coded signal to generate a first signal is done via a first decoding technique, and decoding the separated second coded signal to generate a second signal is done via a second decoding technique which is different from said first decoding technique;
• and
• selecting restoration processing for generating a plurality of channel signals from the first and second signals on the basis of the constituent information.

A decoding method for decoding coded signals, comprising the steps of:

• separating a first coded signal, a second coded signal, and a signal that indicates a selection of the second coded signal from a code string including the first coded signal, the second coded signal, and the signal that indicates the selection of the second coded signal, the first coded signal being generated from a stereo channel included in a plurality of channels, the stereo channel corresponding to a right channel having an acoustic signal and a left channel having another acoustic signal, the second coded signal being selected and coded on a basis of a signal level of the right channel and a signal level of the left channel so that the second coded signal is selected from the group consisting of the right channel, the left channel, and a signal generated by subtracting the right channel from the left channel that is different than the first coded signal;
• decoding the separated first coded signal, second coded signal, and signal that indicates the selection of the second coded signal, respectively, wherein decoding the separated first coded signal is done via a first decoding technique, and decoding the second coded signal is done via a second decoding technique which is different from said first decoding technique;
• and
• restoring a respective output signal for each of the plurality of channels from the decoded first and second coded signals.

A decoding device for decoding coded signals, comprising:

• separating means for separating from a code string a first coded signal, a second coded signal, and constituent information indicating a constituent state of a channel signal constituting the second coded signal;
• decoding means for decoding the separated first and second coded signals, respectively, to generate first and second signals, wherein decoding the separated first coded signal to generate a first signal is done via a first decoding technique, and decoding the separated second coded signal to generate a second signal is done via a second decoding technique which is different from said first decoding technique;
• and
• control means for selecting restoration processing for generating a plurality of channel signals from the first and second signals on the basis of the constituent information.

A decoding device for decoding coded signals, comprising:

• separating means for separating a first coded signal, a second coded signal, and a signal that indicates a selection of the second coded signal from a code string including the first coded signal, the second coded, and the signal that indicates the selection of the second coded signal, the first coded signal being generated from a stereo channel included in a plurality of channels, the stereo channel corresponding to a right channel having an acoustic signal and a left channel having another acoustic signal, the second coded signal being selected and coded on the basis of a signal level of the right channel and a signal level of the left channel so that the second coded signal is selected from the group consisting of the right channel, the left channel, and a signal generated by subtracting the right channel from the left channel that is different than the first coded signal;
• decoding means for decoding the separated first coded signal, second coded signal, and signal that indicates the selection of the second coded signal, respectively, wherein decoding the separated first coded signal is done via a first decoding technique, and decoding the second coded signal is done via a second decoding technique which is different from said first coding technique;
• and
• restoring means for restoring a respective output signal for each of the plurality of channels from the decoded first and second signals.

A computer-readable medium containing instructions for controlling a recording and/or reproducing system to perform a method, the recording and/or reproducing system having a memory, the memory having a code string recorded thereon, the method comprising

• separating a first coded signal, a second coded signal, and a signal that indicates a selection of the second coded signal from the code string including the first coded signal, the second coded signal, and the signal that indicates the selection of the second coded signal, the first coded signal corresponding to a first audio signal generated from a stereo channel included in a plurality of channels, wherein the stereo channel corresponds to a right channel having an acoustic signal and a left channel having another acoustic signal, the second coded signal corresponding to a signal selected on the basis of signal level of the right channel and a signal level of the left channel such that the second coded signal is selected from the group consisting of the right channel, the left channel, and a signal generated by subtracting the right channel from the left channel that is different than the first coded signal;
• decoding the separated first coded signal, second coded signal, and signal that indicates the selection of the second coded signal, respectively, wherein decoding the separated first coded signal is done via a first decoding technique, and decoding the second coded signal is done via a second decoding technique which is different from said first decoding technique;
• and
• restoring a respective output signal for each of the plurality of channels from the decoded first and second coded signals.