| 摘要 |
S1 calculates a common scale factor initial value. Next, S11 corrects the initial value. The initial value of the current frame added by a difference between the initial value and the end value of the preceding frame is made to be a common scale factor corrected initial value. The corrected initial value is used for scaling. If S3 judges that the quantization noise for each sub band is not greater than a permitted noise, S5 performs variable-length encoding and S6 judges whether the code amount after the encoding is not greater than a target code amount. If the code amount is judged to be greater than the target code amount, S7 modifiesthe common scale factor in the direction to increase the quantization step size and control is returned to the quantization process. After this, until the code amount is judged to be not greater than the target code amount, the process is repeated. The corrected initial value can reduce the processing time.
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