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Method of coding an audio signal by using coding unit and an adaptive orthogonal transformation
Method of coding an audio signal by using coding unit and an adaptive orthogonal transformation
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机译:通过使用编码单元和自适应正交变换来编码音频信号的方法
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摘要
A coding unit for coding an audio signal by using an adaptive orthogonal transformation and a coding method comprises calculating the sum total of power of an input audio signal in a time duration of an orthogonal transform length or over the length, adaptively controlling the minimum audible level as a threshold level corresponding to the power level on a frequency axis after the orthogonal transformation or on a time axis before the orthogonal transformation, excepting samples having a power level under the threshold level from orthogonally transformed samples and quantizing remaining samples. The threshold level of the minimum audible level is adaptively controlled corresponding to an observed level of an input audio signal. Even if the input audio signal has various power levels, it is possible to usually set the adaptively audible value (the threshold level), thereby effectively reducing a coding amount.
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