Signal compressing apparatus

1. A signal expanding method comprising the steps of:

receiving an encoding-resultant signal of a predetermined recording-medium format from a digital disc including a DVD, the encoding-resultant signal containing audio information resulting from quantization of an audio signal at a quantization degree higher than a degree of quantization for a CD and at a quantization sampling frequency higher than that for a CD, the quantization sampling frequency including 96 kHz;

using a first decoder and thereby decoding the received encoding-resultant signal into a formatting-resultant signal corresponding to a predetermined format for a digital disc including a DVD, the formatting-resultant signal including segments corresponding to user data areas prescribed in the predetermined format, a compression-resultant signal being placed in the segments of the formatting-resultant signal;

deformatting the formatting-resultant signal into the compression-resultant signal; and

using a second decoder and thereby expanding the compression-resultant signal into a quantization-resultant signal by a Huffman decoding process.

2. A signal expanding method comprising the steps of:

receiving an encoding-resultant signal of a predetermined recording-medium format from a digital disc including a DVD, the encoding-resultant signal containing audio information resulting from quantization of an audio signal at a quantization degree higher than a degree of quantization for a CD and at a quantization sampling frequency higher than that for a CD, the quantization sampling frequency including 96 kHz;

using a first decoder and thereby decoding the received encoding-resultant signal into a formatting-resultant signal corresponding to a predetermined format for a digital disc including a DVD, the formatting-resultant signal including segments corresponding to user data areas prescribed in the predetermined format, a compression-resultant signal being placed in the segments of the formatting-resultant signal;

deformatting the formatting-resultant signal into the compression-resultant signal; and

using a second decoder and thereby expanding the compression-resultant signal into a quantization-resultant signal by one of an orthogonal decoding process and a Huffman decoding process.

3. A signal compressing method comprising the steps of:

quantizing an input audio signal into a quantization-resultant signal at a quantization degree higher than a degree of quantization for a CD and at a quantization sampling frequency higher than that for a CD, the quantization sampling frequency including 96 kHz;

compressing the quantization-resultant signal into a compression-resultant signal by a Huffman encoding process through the use of a first encoder including a Huffman encoder; and

using a second decoder and thereby formatting the compression-resultant signal into a formatting-resultant signal corresponding to a predetermined format for a digital disc including a DVD, the formatting-resultant signal including segments corresponding to user data areas prescribed in the predetermined format, the compression-resultant signal being placed in the segments of the formatting-resultant signal.

4. A signal compressing method as claimed in claim 3 , wherein the compressing step comprises:

1) dividing the quantization-resultant signal into components corresponding to divided frequency bands respectively, and 2) compressing the components according to frequency-band-dependent compression characteristics depending on a predetermined auditory sensation model.