Geometrical attacks can destroy most watermarking systems at present. So how to efficiently resist such kind of attacks remains a challenging direction in watermarking research. In this paper, a novel sequence watermarking scheme, which exploits a geometrical invariant, i.e. average AC energy (AAE) to combat arbitrary geometrical attacks, is presented. The scheme also uses some other measures, such as synchronization and optimal whitening filter to resist other attacks and improve detection performance. The experimental results show that the scheme can efficiently improve the visual quality of the watermarked video and achieve good robustness against random geometrical attacks. The scheme also has good robustness against other attacks, such as low-pass filtering along time axis and frame removal.