Several fast lapped transforms via time-domain pre- and post-processing of the DCT have been developed. Both orthogonal and biorthogonal versions are available. The new transforms enjoy excellent frequency response and the blocking artifact can be eliminated.
Please check here for the type-I orthogonal and biorthogonal TDLT.
Fig. 1 shows the structure of the type-II fast orthogonal TDLT, which is very similar to Dr. Malvar's type-I fast lapped orthogonal transform (LOT-I).
Fig. 1. General structure of the TDLOT-II.
Fig. 2. Frequency response of the optimized 8x12 TDLOT-II.
Fig. 4. General structure of the TDLBT-III.
For more information, please check the paper:
J. Liang, C. Tu, and T. D. Tran, "Lapped transform via time-domain pre- and post-filtering. Part II: fast algorithms," submitted to IEEE Trans. on Signal Processing, Oct. 2001. PostScript | PDF