Recursive discrete cosine transforms with selectable fixed-coefficient filters

In this work, we propose new fixed-coefficient recursive structures for computing discrete cosine transforms with the power-of-two length. The fixed-coefficient recursive structures are developed by exploring the periodicity embedded in transform bases, whose indices can form a complete residue system or a complete odd residue system. After simple data manipulation, the proposed filtering structures requiring fixed-coefficient multipliers are better than the previous recursive methods which need general multipliers in filter realization. In particular, we found that the properly selected fixed-coefficient fitters achieve lower roundoff errors than the nominal variable-coefficient ones for computing DCTs in finite-word-length machines.