We proposed a novel digital video watermarking that embeds dual watermarks in the block DCT domain to solve the deadlock problem. Daul watermarks are composed of private watermarks and robust blind watermarks. Firstly, private watermarks are embedded into the lowest AC coefficients of the P or B-frames in accordance with the motion direction gained from a previous frame. Secondly, blind watermarks that have the robustness are inserted into the DC coefficients of the I-frames using a private key made from temporal I-frame motion information. Thus, when a deadlock situation occurs, the proposed algorithm can efficiently solve the problem. Experimental results confirmed that the proposed algorithm can produce good subjective and objective results for MPEG coding with a variety of bit rates. Furthermore, the proposed watermarking algorithm can potentially be applied to broadcasting monitoring systems due to its simplicity and high robustness.