Improvement of carrier capacity for scalable scrambling method with reversible information insertion functionality

This paper proposes a scalable data representation scheme to improve the carrier capacity of a data hiding method called ScaScraIH [1] in the DCT compressed domain. Though ScaScraIH can scalably scramble a DCT compressed content such as JPEG image and MPEG/H.26x video while inserting external information into it, the manipulated content suffers from consistent bitstream size increment. To better justify the inevitable bitstream size increment, we propose a data representation scheme called virtual queue decomposition to scalably increase the carrier capacity of ScaScraIH without further increasing bitstream size of the output product. Virtual queue decomposition puts zerorun-value pairs into a fixed number of sub-queues, where the cardinality of each sub-queue together form a unique decomposition that encodes a segment of the external information. Carrier capacity is increased by simply increasing the number of sub-queues, but at the expense of higher computational complexity. Analysis is carried out to compute the theoretical upper bound for carrier capacity with respect to ScaScraIH. Experiments are also carried out to verify the proposed improvement.