| 摘要 |
PURPOSE: An audio encoder/decoder apparatus and method is provided to perform a scale adjusting function by one structure and processing multiple contents at the same time. CONSTITUTION: The first filter(100) separates an input audio signal into low-frequency and high-frequency signals. The second filter(110) separates the low-frequency signal into a fine frequency band. An ADPCM encoder(120) encodes an output signal of the second filter(110) into a digital signal by an ADPCM type. A time-to-frequency conversion part(130) converts the high-frequency signal of a time domain into a frequency domain. A bit alignment and quantization part(140) bit-aligns and quantizes an output signal of the conversion part(130). The first bit stream forming part(150) forms a bit stream using the encoded signal, the quantized bits, position information of contents, and a process mode. A sound processing part(160) processes the low-frequency and high-frequency signals according to a sound psychological model to adjust a delta value of a quantizer used in the encoder(120). A control part(170) provides the process mode and the position information of contents. A prediction part(180) gets correlation between previous frame information of the part(150) and present frame information, and a bit stream forming part(190) reduces repeated data according to the calculated correlation information to form a bit stream.
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