technicalreports

Advisor: Dr. Javed I. Khan
Department of Computer Science
Kent State University
May 2004

The Internet is popularly used in all the fields and all over the world. The abrupt growing of applications and businesses via the Internet leads to a heavy traffic on it. To solve network congestion problems has become useful and urgent, and it has also been one of the most active research topics in this field. In this work, the Active Video Transcoding (AVT) technologies are studied to transfer video streams on asymmetric networks and avoid data blocking or breaking. The AVT sits on the Active Network to enable implementing dynamic adaptations for a pre-encoded video stream to match the available bandwidth of heterogeneous networks. As two of the important AVT technologies, the Symbiotic Rate Control (SRC) and the Focal Area Resolution Control (FARC) technologies have been studied for MPEG-2 video stream transferring. Both SRC and FARC choose the quatization step size of MPEG-2 (mquant) as implant point to communicate with MPEG-2 and adjust the bit rate to adapt the network situation dynamically and intelligently. The SRC works on the frame level while the FARC works on the macro-block levels. The SRC adjusts the bit rate of transferring video via mquant according to the network situation to avoid network congestion, it sacrifices video quality somewhat to improve network traffic in bad situations. As complement to avoid sacrificing the video quality, the FARC enhances the image quality in the interesting areas via mquant, such that, the video can be transmitted and played at a lower bit rate but still having good image quality in focal areas. The numerical schemes and sample programs for the SRC and FARC have been developed basis on the MPEG-2 TM5. Experiments in an imitated active network environment have successfully demonstrated the functionality of SRC and FARC. The research results, schemes and codes obtained in this work may be useful in both guiding the future research activities and implementing commercial AVTs in the next generation networks--the commercial Active Networks.

Thesis Title:

SYMBIOTIC RATE CONTROL AND FOCAL AREA RESOLUTION CONTROL OF MPEG2 TRANSCODER