In the ubiquitous environment, seamless video streaming requires content adaptation technologies to meet the QoS. But video transcoding that is one of the content adaptation, would distort the watermark signal embedded in the video content. In this paper, we propose a watermark system that guarantees watermark detection after the video transcoding. We analyze the effect of the video transcoding on embedded watermark and generate metadata of watermark detectable condition. In the experiments, we use general image watermarking algorithms and apply those watermarking algorithms to the video. Experimental results show that the proposed watermarking system can be safely used with the video transcoding.