Early Detection of All Zero Chroma Blocks in H.263

摘要

In very low bit rate video coding, large quantization parameter makes many blocks to be all zero blocks. Based on the algorithm using SAD of luma to detect the zero luma blocks, this paper proposed an algorithm using SAD of luma obtianed in motion estimation to predict SAD of chroma, which is further used to detect the zero chroma blocks. Experimental results show that the proposed algorithm reduces the computation for DCT operations including DCT and quantization by up to 64percent with negligible image quality degradation. Furthermore, the prediction process is very simple and easy to be implemented in H.263 encoder.