With the widespread adoption of 5G networks, high-speed video downloading and distribution have become easier, allowing a mobile device to transfer several gigabytes of movies in a short period. This poses significant challenges to video copyright protection. For common piracy scenarios, such as screen recording, the robustness requirements for video watermarks have become more stringent. Compressed domain video watermarks have advantages such as lower computational complexity and higher embedding efficiency. However, there are also some obvious disadvantages. Firstly, there are issues related to video processing formats; some video decoders designed for specific formats may not correctly process compressed bitstreams embedded with watermark information, leading to compatibility problems. Secondly, the robustness against format conversion attacks is not high. This is because different video formats use different compression algorithms, and the watermark information in the compressed domain may be lost or distorted during format conversion, affecting the effectiveness of the watermark. To address these issues, this paper proposes a robust video watermarking method based on DT CWT, achieving better resistance to heavy compression attacks with a simpler scheme. Tests have shown that this system can effectively meet the requirements for robust video watermarking, exhibiting good robustness with an average BCR of 0.88 between the extracted watermark and the original watermark. Additionally, compared to conventional compressed domain video watermarking schemes, the proposed method in this paper improves the watermark Bit Correct Rate (BCR) by 3% under high compression ratios.