| 摘要 |
There is provided an encoding and decoding apparatus which can provide a high quality reproduction sound. There are provided an encoding section (1, 2, 3, 4, and 5) and a decoding section (7, 8, and 9) . A block length determining section (1) of the encoding section time-sharingly divides an input signal into blocks having a block length corresponding to the degree of change of the input signal. A frequency band dividing section (2) divides the signal of each block into a plurality of frequency bands. A bit allocating section (3) obtains a masking threshold value-to-noise ratio of each frequency band from the magnitude of the power of each frequency band reflecting a psychoacoustic characteristic, and determines the amount of quantization bits to be allocated to each frequency band based on the magnitude of the masking threshold value-to-noise ratio. A quantizing section (4) generates a code string by quantizing the signal while allocating a specified amount of bits to each frequency band based on information from the bit allocating section (3). The bit allocating section (3) receives information representing the block length from the block length determining section (1), and adopts a varied psychoacoustic characteristic according to the block length. <IMAGE> |
