在音訊編解碼的過程當中，MDCT與IMDCT主要是對訊號做時域轉頻域或頻域轉時域時的運算，而這個步驟佔了音訊編解碼的過程中極大部分的運算量；由之前的經驗與推導可以發現MDCT與IMDCT皆為以DCT-IV為核心的型式，因此可以採用共架構的型式來實現；我們針對MDCT與IMDCT提出一個快速運算的共架構演算法，經由少量的前處理來減少核心的運算量，並以IDCT-II為核心來計算；優點在於MDCT與IMDCT可以共用同一套硬體的運算流程、降低硬體實現成本，且核心運算速度為(N2/64 + N/4) 個cycles，和原始定義需要(N2/2) 個cycles相比較起來有著龐大的改善，和參考文獻比較起來也有顯著的改良。

In audio coding and decoding flow, the major purpose of MDCT and IMDCT are to convert time domain into frequency domain and to convert frequency domain into time domain, respectively, and this step accounts great part of the computation in audio codec. Derived from previous experience, we can found that both MDCT and IMDCT can be found to a kernel type of DCT-IV, which can be employed a single hardware accelerator through this IDCT-II kernel to share the hardware resources. Fast algorithm based on a unified recursive IDCT-II is derived for MDCT and IMDCT, and we can reduce the kernel consideration by using pre-processing steps. Hence, the proposed design would reduce the hardware costs in implementation of MDCT and IMDCT on a platform of audio codec. The proposed algorithm takes (N2/64 + N/4) computational cycles for computing all output sequences, which achieve a great improvement than original definition algorithm that needs (N2/2) computational cycles. The proposed algorithm also has a significant improvement than other previous algorithm.

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