In this paper, we propose a robust and invisible video watermarking scheme. To ensure robustness against various non-hostile disturbances which can occur during the distribution of digital content, the proposed system selects certain blocks using a robust and imperceptible block selection scheme and watermarks are embedded into these blocks using spread-spectrum watermarking in DCT domain. In addition, visual masking is applied to the watermarking embedding process for high invisibility. Our system is designed to extract 16 bits data in any 15-second interval. Experimental results show that the proposed system offers high invisibility and that it is robust against MPEG-4 compression and DA-AD conversion.