| As the rapid development of computer technology, we are concerning on the techonology which make end-usre device small,smart and designed for special function, like poked PC, smart phone. Embedded technology provides a flexible, efficient and cost-effective solution for this trend. Embedd System has features as follows:function-customized, small size, mobilization and increasing close to network.In the telecom industry, the bandwidth of network is raising, data service is available for all, the technology for multimedia device is mature, all of which make us not satisfied with voice phone call.Making video call using Internet has already became the key area in communication. Compared with current on-service networks, like 2G/3Q WLAN, IP network is best fit for video phone call because of its good performance on bandwidth utilization, cost and configure.Considering trendency of technology and requirement of market, "Video Transmit Device" project is put forward to."Video Transmit Device" is a embedded device designed for real-time video transmission. It uses ADSL/LAN to connect with Internet/VPN network. With the I/O device, like TV and camera, it can provide voice, video,attachment,e-mail communication."Video Transmit Device" chooses i.MX27 multimedia applications processor produced by Freescale Company as hardward platform, Linux OS with kernel 2.6.19.It use H.264/MPEG as video standard, G.711/G.721/GSM/SPEEX as voice standard, communication protocol select SIP stack. Open-source software Linphone is applied in this project charging for the mission on application layer. MiniGUI is a tool we use to develop the GUI for this project. Also, we make use of embedded database and embedded web server technology to increase the control of the device.This essay started from introduction of embedded system and the method of developing embedded system.Then base on the "Video Transmit Device" project, it emphazie on the key embedded techonology applied on the i.MX27 development board. There are three important chapter, respectively introduce the features, application and development procedure of MiniGUI, SQLite and Boa Server. |
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