| 摘要 |
A degrouping method for an MPEG 1 decoder for degrouping three consecutive subband samples (X, Y and Z) compressed into one codeword &copy& by a step number (N) includes the steps determining whether the value of the step number is 3, determining whether the value of the step number is 5 if the value of the step number is not 3, determining whether the value of the step number is 9 if the value of the step number is not 5, searching corresponding values of the subband samples from a first look-up table in the sequence of Z, Y and X, if the value of the step number is 3, searching corresponding values of the subband samples from a second look-up table in the sequence of Z, Y and X, if the value of the step number is 5, and searching corresponding values of the subband samples from a third look-up table in the sequence of Z, Y and X, if the value of the step number is 9, wherein the first, second and third look-up tables have the respective values of the subband samples corresponding to the codeword value. Since the MPEG 1 degrouping method obtains subband samples using look-up tables without using a divider, the number of required cycles is considerably reduced.
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