MDCT/IMDCT performs the conversion between the time-domain signal and the frequency representation in the high quality audio codec system, which is based on the concept of time-domain aliasing cancellation. Using the N/8-point FFT kernel, a new MDCT/IMDCT general structure is presented in this paper. The computation rate and the data throughput per transformation of the system are twice as much as the latest algorithm, utilizing both the paralleling procedure and the butterfly unit. In addition, the analyzed results of FPGA implementation on Altera Stratix Device show the proposed structure provides a superior performance in terms of computation speed and data throughput.