Improved Upsampling Filter Design for Spatially Scalable Video Coding

摘要

Scalable video coding is an ongoing standard, and the current working draft (WD) is to be finalized as an extension of H.264/ AVC. It provides scalability at the bit stream level with good compression efficiency and allowing free combinations of spatial, temporal and quality scalability. In the WD, a uniform up-sampling filter is employed to interpolate the base layer frames. This technique achieves high interpolated precision for both luma component and chroma components, but it results in extremely large encoding time which obstructs it from practical use. This paper proposes an improved up-sampling filter design for spatially scalable video coding. It makes use of a basic characteristic of human vision system and intends to assign different filters for different components. Specifically, current usage of the 6-tap up-sampling filter is only for luma component, but for chroma components, much more simplified filter such as 4-tap filter or 2-tap filter should be used instead. Experimental results show that improved up-sampling filter design reduces the computational complexity significantly with negligible coding loss and bit-rate increases.