In this paper, a novel adaptive approach to spatial domain video watermark- ing is presented. It takes full advantage of both intra-frame and inter-frame information of video content to guarantee the perceptual invisibility and robustness of the watermark. An effective block classifier is delicately designed based on motion information and region complexity. Meanwhile, the idea of bitplane replacement is introduced in the embedding procedure. A major advantage of this technique is that the watermark can be extracted without referring to the original video while embedded adaptively in accordance with the human visual system and signal characteristics. The multi-frame based extraction strat- egy ensures that the watermark can be correctly recovered from a very short segment of video. Individual frames extracted from the video also contain watermark information. Experimental results show that the watermarked video appears visually indistinguishable from the original video, and the proposed watermarking technique is robust enough to common video attacks. Keywords: Copyright protection, Digital watermarking, Video watermarking, Adaptive algorithm