Design & Implementation Of A Wireless Video Conference System Based On Mobile Device

The paper mainly investigates how to implement a wireless video conference system on the hardware platform based on Intel Xscale PXA270 microprocessor. The software platform is an embedded Windows CE 5.0 OS. T'he hardware of the system includes an Xscale PXA270 core processing module, a wireless interface module, a graphic data acquisition module, an audio processing module and a LCD touch screen displaying module. On software it's composed of audio-video processing function, audio and video synchronizing function, audio and video data secrecy function , multicast transmission function.This paper introduces the G.729A audio and H.264 video code-and-decode arithmetic as well as their implementation, the AES data Encryption and the RTP/RTCP protocol to ensure the real time transport used in this wireless video conference system in detail. It advances a scheme to ensure the security of transporting the IP multicast in the Internet using Windows Active Directory and the Lightweight Directory Access Protocol. And also realizes the synchronization of video and audio simply using the timestamp message in RTP package head accoding to the RTP/RTCP protocol theory.Moreover, this paper deeply analyzes the DirectShow technology, disposes multimedia data using the DirectShow technology, designs and implements the wireless video conference system according to the DirectShow technology's framework. This system integrates audio-video processing function, audio and video synchronizing function, audio and video data secrecy function, multicast transmission function into the DirectShow framework, efficiently implements the video conference system which can conveniently increase or delete the function module. It reaches the object, meets the demands of video conference system, and will have a vast of market foreground.