A New Recursive Decomposition Algorithm to Calculate IMDCT

A new decomposition method to calculate IMDCT is proposed in this paper. The decomposition algorithm can convert a pair of long transforms into 2 pairs of short transforms with half size of the long transforms. In addition, the decomposition algorithm can be utilized recursively to attain shorter transforms and reduce computational cycles. According to experimental results obtained previously, the number of computational cycles of 512-point IMDCT is estimated to be 9641, which is less than those in previous reports.