Title:
【発明の名称】音響信号符号化方法、音響信号復号化方法
Document Type and Number:
Japanese Patent JP3317470
Kind Code:
B2
Abstract:
PURPOSE: To efficiently encode an acoustic signal and to obtain a decoded acoustic signal of high quality by encoding the acoustic signal while selecting a coding method suitable for a feature, a characteristic of an input acoustic signal. CONSTITUTION: An input acoustic signal from an input terminal 11 is supplied to either a first coding part (CELP coding part) 12 or a second coding part (TWIN coding part) 41 through a mode switchover part 65. The input acoustic signal is inputted to a feature extraction part 66 also. The feature extraction part 66 extracts its feature at every short time frame of the input acoustic signal to control the mode switchover part 65. That is, the feature extraction part 66 divides e.g. respective short time frames of the input acoustic signal into four sub-frames, and obtains mean power or mean spectrum envelope of respective divided sub-frames, and obtains the change rate of the mean power or the change rate of the mean spectrum envelope, and controls the mode switchover part 65 so as to select the coding by the first coding part 12 when the change rate is a prescribed value or above, and to select the coding by the second coding part 41 when the change rate is the prescribed value or below.
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Inventors:
Kazunaga Ikeda
Naoki Iwakami
Takehiro Moriya
Satoshi Miki
Naoki Iwakami
Takehiro Moriya
Satoshi Miki
Application Number:
JP6961995A
Publication Date:
August 26, 2002
Filing Date:
March 28, 1995
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
G10L19/00; G10L19/038; G10L19/04; G10L19/08; G10L19/16; G10L19/22; H03M7/30; (IPC1-7): G10L19/00; G10L19/04; G10L19/08; H03M7/30
Domestic Patent References:
| JP6503896A |
Attorney, Agent or Firm:
Suguru Kusano