Research On Network Technology For Visual Phone With NVD Player

Today, in the modern society with information technology highly developed, traditional phone service can not meet people's demand of communication any more, and visual phone based on Internet is more and more popular. But all former visual phones were not welcome by market because their prices were much higher than traditional phones.With rich I/O interfaces and strong ability to play audio and video, NVD player can play movies, music and pictures on disks, network file systems and USB devices.With the existing hardware and software in the"NVD Player - Television"system, few additional input devices and related software developed, the original media playback system can be improved into a brand new consumption electronics device with both two kinds of functions: entertainment and communication.With deep understanding of the NVD player's embedded system, a reasonable outline of NVD-PHONE was obtained and then the whole system was developed according the outline. The system consists of server and clients. The server is in charge of the management of the information of all clients. Clients get to discover each other by the information from the server. If necessary, server should help clients to establish the communication and transport Audio/Video (A/V) data between them. Users can access the system by the GUI on TV and a remote. During the R & D process, several modules were designed and implemented including: management of clients'status and information, transplanting of A/V input device drivers, communication of A/V data, startup and closure of communications, sound and image capture, exceptions handling, etc.The eventual functional test showed the NVD-PHONE worked well. And through the quantitative performance test, it was learned how the network environment variables (such as network latency, latency variation, packet loss rate) could affect the system, and some useful data and conclusion was obtained.