VSYNC: a novel video file synchronization protocol

ABSTRACT

VSYNC is a novel incremental video file synchronization system that efficiently synchronizes two video files at remote ends through a bi-directional communications link. Retransmission of a video file that has been modified only slightly, for the purpose of synchronization with a remote-end copy, is extremely expensive but avoidable. VSYNC is a bi-directional algorithm designed to automatically detect and transmit changes in the modified video file without the knowledge of what was changed. Another feature of VSYNC is that it allows synchronization to within some user defined distortion constraint. A hierarchical hashing scheme is designed to compare video chunks, converting the high-level content information to a low-level hash stream that is more amenable to the tools of coding theory. Our approach shows impressive gains in transmission rate-savings. In a typical example of two 12 sec video files with about 10% of the frames being edited, transmission savings of 44% to 87% can be obtained compared to directly sending the updated video files using H.264 and rsync [1].

REFERENCES

• 1: A. Tridgell and P. Mackerras, "The rsync algorithm," http://rsync.samba.org/, Nov 1998.
• 2: Jiri Fridrich, Robust Hash Functions for Digital Watermarking, Proceedings of the The International Conference on Information Technology: Coding and Computing (ITCC'00), p.178, March 27-29, 2000
• 3: B. Coskun and B. Sankur, "Robust video hash extraction," IEEE 12th Proceedings on Signal Processing and Communications Applications, pp. 292--295, 2004.
• 4: Y. Lin, D. Varodayan, and B. Girod, "Image Authentication and Tampering Localization using Distributed Source Coding," IEEE 9th Workshop on Multimedia Signal Processing, pp. 393--396, 2007.
• 5: S. Draper, A. Khisti, E. Martinian, A. Vetro, and J. Yedidia, "Using Distributed Source Coding to Secure Fingerprint Biometrics," IEEE International Conference on Acoustics, Speech and Signal Processing, vol. 2, 2007.
• 6: T. Richardson, M. Shokrollahi, and R. Urbanke, "Design of capacity-approaching irregular low-density parity-checkcodes," Information Theory, IEEE Transactions on, vol. 47, no. 2, pp. 619--637, 2001.
• 7: C. Yeo, P. Ahammad, and K. Ramchandran, "Rate-efficient Visual Correspondences using Random Projections," to appear in IEEE International Conference on Image Processing, 2008.
• 8: R. Puri, A. Majumdar, and K. Ramchandran, "PRISM: A Video Coding Paradigm With Motion Estimation at the Decoder," IEEE Transactions on Image Processing, vol. 16, no. 10, pp. 2436--2448, 2007.
• 9: B. Girod, A. Aaron, S. Rane, and D. Rebollo-Monedero, "Distributed video coding," Proceedings of the IEEE, vol. 93, no. 1, pp. 71--83, 2005.

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.4 INFORMATION SYSTEMS APPLICATIONS
      H.4.m Miscellaneous

General Terms:
Design

Keywords:
rsync, video file synchronization, video hash, vsync, zsync