* The following paper is a pre-print. The publication is currently
under review for IEEE Transactions on Information Forensics and Security
(TIFS) Access Paper or Ask Questions
* Submitted to TPAMI journal on Apr. 22, 2015. Decision of "Revise and
resubmit as new" received on Sep. 10, 2015. At present, updating the paper to
address the feedback and concerns of the two reviewers. The re-submitted
paper will be uploaded as version 2 on arXiv Access Paper or Ask Questions