| With the rapid development of computer science and internet, the new technology of stream media can satisfy our requirements which we can get multimedia information immediately. The technology of stream media can play a video by streaming transport based on RTP/RTCP after a short time. It can be widely used in Digital Video Broadcasting, Video Conference, Distance Education and so on. Embedded System is one of hotspot in research field. It has some characteristics such as low power, small, highly integrated and expertise. Embedded system was mainly applied for military and aerospace in early. With the development of internet, the embedded system is and will be used in IA (Information Appliance) and 3C(Computer, Communication & Consumer).Therefore, it will be very promising to research the tramsmission method of stream media based on ARM.This thesis is based on a real project of a company in Nanjing, "multimedia in elevator". It combines embedded system and stream media in elevator and makes people get multimedia information anywhere.First, this thesis studys some related technologies of stream media,researchs deeply the RTP/RTCP protocol, mastering its structure and rules. Researchs the QoS of the technology of control in the realtime transmission. Researchs and analyzes the methods of transmission control which has had, analyzes the characteristics of stream media and embedded system.Secondly, this thesis analyzes deeply the based on window design in congestion control and rate-based congestion control,analyzes their principium and application range, and improves on the rate-based of sender congestion control in rate-based congestion control, designs a method that based on the buffer of receiver. It can assist to change the rate of sending by setting and checking the critical point of buffer. It can improve the quality of tramsmission of stream media effectively and avoid the network congestion.Finally, this thesis introduces linux system porting. Analyzes the JRTPLIB library which is a open source code to implement the RTP/RTCP and modifies the Structure of RR report in RTCP for the real requirements of project. Design a system based on it to implement the trarnsmission method of stream media of the rate-based of sender and the buffer of receiver. |
