A Fast Two-Dimension 4×4 Inverse Integer Transform Algorithm for Real-time H.264 Decoder

ABSTRACT. This Paper presents a new fast two-dimensional 4×4 (2-D 4×4) inverse integer transform algorithm. The algorithm takes advantage of the symmetries of basic images and makes use of the characteristic of the transform data of practical videos. Compared to other fast algorithms, the number of addition and shift operations for the inverse transform can be reduced greatly. Numerical results on several standard video clips indicate that on average, for a 4×4 block, the new algorithm needs 12.7838 addition operations and 1.69536 shift operations, which are much less than the other algorithms need. Moreover, the new 2-D algorithm can be parallelized easily.