Simplified three-dimensional discrete cosine transform-based video codec
Jari J. Koivusaari, Jarmo Takala · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
In this paper, a simplified three-dimensional discrete cosine transform (3D DCT) based video codec is proposed. The computational complexity of the baseline 3D DCT based video codec is reduced by simplifying the transformation block. In video sequences with low motion activity, consecutive images are highly correlated in the temporal dimension, thus the DCT does not usually produce significant coefficient values to the higher temporal frequencies. Therefore, we have a possibility to use a simple averaging operation and the 2D DCT, instead of the full 3D DCT operation, for some of the cubes in processing. Furthermore, some of the resulting cubes could be combined together to achieve more efficient binary representation. Based on our results, simplifications considerably improved compression efficiency of the 3D DCT based codec for video sequences with low motion activity. In addition, the compression efficiency for video sequences with high motion activity was maintained. At the same time, the coding speed of the simplified 3D DCT based video codec was increased from the original. Although the compression efficiency of H.263 video codec was not reached, the encoding speed of the 3D DCT based video encoder was many times faster than the encoding speed of the H.263.