Low Complexity H.264 Transcoder for Bitrate Reduction

The paper presents a fast homogenous H.264 video transcoding algorithm in order to reduce the bitrate. We propose a fast mode decision algorithm by using the frame activity based on motion vector (MV) in input bitstream. In the proposed algorithm, the frame activity reflects a degree of macroblock (MB) mode variation between pre-coded bitstream and transcoded bitstream which degrades the rate-distortion (RD) performance significantly due to variable block size in H.264. Experimental results show that the proposed algorithm can be effectively applied to the H.264 video transcoder for the lower complexity and the better quality