We propose a novel, low-complexity, tracking scheme that uses motion vectors directly from a video coder. We compare our tracking algorithm against ground truth data, and show that we can achieve a high level of accuracy, even though the motion vectors are rate-distortion optimized and do not represent true motion. We develop a framework for tracking in video sequences with various GOP structures. Such a scheme would find applications in the context of Mobile Augmented Reality. The proposed feature tracking algorithm can significantly reduce the required rate of feature extraction and matching.