An Adaptive Streaming System Based On RTSP

Streaming media is a technology that can help transport media over the Internet aftercompressing a series of media datum. Using this technology, the clients can play media justafter filling local buffer with a few seconds of data, instead of downloading the complete file.With the development and wide adoption of IPTV, TS (Transport Stream) is used widely. TSwas designed in the original purpose of meeting the need of playing media at any point oftime. Apple Inc. has made TS worked on IPhone, IPad and other devices; besides, an adaptivestreaming technology based on HTTP and TS, i.e. Http Live Streaming, has been developedand publicized by Apple. However, an adaptive streaming based on TS and RTSP server,another popular streaming server, is seldom seen. For this reason, this article has designed andimplemented an adaptive streaming system based on RTSP and TS.The core work of this article contains:1. Modifying DSS (Darwin Streaming Server) tomake it support TS and developing client;2.Designing an adaptive control policy;3.Designing a jitter measurement that applies to our RTSP system with combining the feature ofconventional MDI:DF (Media Delivery Index Delay Factor) and OWDP (One way DelayPacket Loss Protocol).Experiments show that when threshold value of jitter is set to100milliseconds withmeasurement interval1second, if there are3times when the measured jitter is greater thanthe threshold, the accuracy rate of predicting packet loss by our jitter measurement will reach80%.At last, the design of this article realizes:1. Comparing with non-adaptive system withthe same bandwidth, we can improve the play quality of client.2. The utility of decodingbuffer will converge into a reasonable rage rapidly.3. Under the condition of low bandwidth,the case of short pause and mosaic when playing media will be reduced significantly for wecan decrease the packet loss largely.