The Research And Implementation Of Video Phone Base On Windows CE

VOIP(Voice Over Internet Protocol) is a digital technology of voice -transferring based on ip nerworks, which is identified by voice packet-switch. During the past 10 years, VOIP technology has been becoming maturer and maturer, and the VOIP industry is also developing very fast. Meanwhile, with the development of the embedded technology, the application of embedded system has extended from control system to consumer electronics. The combination of embedded and network communication has attracted more and more attention. Embedded VOIP terminal will be an important application of embedded system.SIP(Session Initiation Protocol)is a signaling protocol brought up by IETF. The design of SIP refers to the thought of many mature internet standards and protocols. SIP message uses text format, which is adapted to embedded system with less computing abilities. SIP has good expansibility, mobility and media-negotiation. All these characteristics are helpful to enhancing the interoperability, openability and compatibility between the embedded network devices.Therefore, this paper proposes applying SIP to the embedded system bases on Windows CE, and validates the feasibility of the thought by designing and implementing the product of VOIP terminal in Windows CE.This paper studies on the architecture, realization, message mechanism and signaling flow of SIP/RTP/RTCP and puts great emphasis on the application of SIP stack with reference to excellent open-source SIP/RTP stack, OSIP/JRTP.It proposes the system structure of embedded SIP terminal, and builds the embedded hardware Platform with Samsung S3C2440 , which is of ARM9 arehitecture. It ports Windows CE 5.0 to S3C2440, and at last designs and implements VOIP terminal in Windows CE based on these theories.This system proposes a synchronous solution based on the RTP/RTCP protocol taking account of the features of the embedded system and the controllable technology about audio and video coding in speed(AMR-WB,H.264). In the end, the audio-video synchronous quality has been enhanced.At last , this paper completes test of VOIP terminal prototype device in Windows CE and analyzes the testing result.These results show that the plan this paper has proposed is correct.