Abstract: In this paper, we propose a scalable video coding algorithm for low bit rate failure-free video transmission. In the failure-free video transmission, two channels are utilized to transmit the same video source. In the receiver, the video can be reconstructed by any single encoded bitstream. While receiving two encoded bitstreams, the image quality can be improved by combining two bitstreams. In this paper, we develop a motion vector refinement technique to improve the image quality. In the encoder, the positions of the macroblocks for channel two are shifted by eight pixels from channel one. In the receiver, the motion vectors transmitted in each channel can be refined to more accurate motion vectors with smaller block size when two channels are received. The final decoded image is merged from the two reconstructed images by two channels. Experimental results show our proposed method has high efficiency and high reliability.