Study On The Video Communication Technology Based On SIP Protocol For Android

With the rapid development of high-speed wireless network, the wide application of multimedia technology and the improvement of embedded chip Processing capacity, multimedia terminal has become more and more miniaturized and embedded. On this basis, the embedded mobile terminal operating system arise, Android system is one of the most typical one. Launched by GOOGLE, Android platform is an open source mobile phone operating system based on linux2.6 kernel, and is a completely open system, which has become the research focus in the field of intelligent terminals.Because VOIP technology broke the traditional circuit-switched way, and transmits multi-media information such as audio and video by IP network, which makes people's communication cost sharply. Meanwhile, people's requirements of communication anytime and anywhere accelerate the development of VOIP mobile terminal. Because of the open source of Android system, Android intelligent mobile terminal has a great advantage in price. Therefore, this paper combining with the above advantages, based on Android system, relying on more flexible SIP protocol in VOIP technology areas, combining the WiFi wireless network technology, studies how to realize the Video communication based on SIP protocol on the Android system, short for SVFA (SIP Video For Android). While using this system on mobile phone, based on transmission of audio in WiFi wireless network, blending in video data is more complied with people's face-to-face communication habits. Because of using WiFi connection to the hotspot, communication costs lower than 3G mobile, at the same time, that traditional mobile terminal get IP address more increases its flexibility of access to network.Based on studying Android system, the paper proposed the enabling framework of SVFA, designed and wrote an audio and video collection program for NAVID terga2 hardware board, and proposed an audio and video codec solution suitable for wireless network transmission. To ensure Qos of this system, the paper discussed key technologies in Wireless audio and video transmission process in detail and improved the algorithm. Through studying SIP protocol stack (Mjsip), the paper designed and realized SIP signaling module. In addition, NAT traversal was studied.This thesis mainly designed and implemented four modules including media module, wireless real-time transmission module, SIP signaling module, NAT traversal module. Each module gives detailed work flow.Finally, after designing and implementing the above modules, set up the system environment and tested the system. Experiments show that video calls smooth, the scheme this article designed can be applied in real life, and can provide convenience for people's communicate anytime, anywhere.