| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for embedding interference sound in an acoustic signal which applies prescribed alteration to the acoustic signal such that the interference sound will not be heard at the time of reproducing the altered acoustic signal, and if the sound generated by reproduction of the altered acoustic signal has been obtained by recording or compression processing, allowing the interference sound generated at the time of reproducing the obtained duplicate acoustic signal to be heard.SOLUTION: In an acoustic signal, frequency conversion is applied to odd-numbered and even-numbered acoustic frames, an odd number window spectrum and even number window spectrum are obtained, and alteration is applied such that mutually corresponding odd number spectrum aggregation component and even number aggregation component in an altered frequency band will reflect by prescribed ratios α, &bgr; of their respective values. |
