  As with EAST (Experimental Advanced Superconducting Tokamak) experimental
data analyzed by more and more collaborators, the experimental videos which
directly reflect the real status of vacuum attract more and more researchers'
attention. The real time VOD (Video On Demand) system based on MDSplus allows
users reading the video frames in real time as same as the signal data which is
also stored in the MDSplus database. User can display the plasma discharge
videos and analyze videos frame by frame through jScope or our VOD web station.
The system mainly includes the frames storing and frames displaying. The frames
storing application accepts shot information by using socket TCP communication
firstly, then reads video frames through disk mapping, finally stores them into
MDSplus. The displaying process is implemented through B/S (Browser/Server)
framework, it uses PHP and JavaScript to realize VOD function and read frames
information from MDSplus. The system offers a unit way to access and backup
experimental data and video during the EAST experiment, which is of great
benefit to EAST experimenter than the formal VOD system in VOD function and
real time performance.
