| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for encoding an acoustic signal excellent with less deterioration of sound quality. SOLUTION: An acoustic signal processing apparatus 10 is provided with a band dividing filter 11 for dividing the input acoustic signal for every frequency band, an ADPCM quantizing means 13 for quantizing each frequency band with a predetermined number of bits and a bit stream generating means 23 for shaping the quantized signal into a bit stream, and converts the acoustic signal transmitted to another party through a communication line into an encoded bit stream and outputs it to a communication apparatus main. The acoustic signal processing apparatus 10 is also provided with an ADPCM inverse-quantizing means 15 for inverse-quantizing the quantized signal, a data accumulating means 17 for accumulating the inverse-quantized signal during a plurality of frames, an energy calculating means 19 for calculating energy of the accumulated signal and a bit distribution calculating means 21 for calculating the number of bits required for quantizing from the energy of the accumulated signal, and determines the number of quantization bits used in the ADPCM quantization means 13. |
