In order to deal with the copyright issues in DVB environment

a MPEG domain watermarking algorithm is proposed here.The watermark is embedded by modulation of corresponding DCT coefficients according to human visual system.The threshold of the detection correlator is dynamically adjusted along the time-axis to fit the frame characteristics.The proposed method is of low complexity and easy to be implemented in terminal consumer electronics devices.It has enough robustness in the copy control and user tracing scenarios.