H.264 and AVS Based Streaming Media Transmission Technology Research

With the rapid development of Internet, audio and video resources instead of text and graphs are becoming more and more popular. And the reality and interactivity are paied more attention. Traditional transmission of audio/video over Internet is downloading resource completely firstly and then play it. The downloading (downloaded) process usually takes several minutes even hours which restricts people’s intercourse over Internet through audio and video.In this case, streaming media technology appears.

With streaming media technology, server can transmit data as a stream and deliver audio/video/cartoon orderly to client continuously. Users need not to wait for complete download of the file and just wait several or tens of seconds of start delay before playing. The remaining part of the file continues to download from the server while audio/video is being played on user’s computer.H.264/AVC is a new generation video coding standard which is developed by Joint Video Team composed of ITU-T VCEG and ISO MPEG. Compared to existing video compression standard and technology, H.264 not only has more efficient compression performance, but also has good network adaptability. Therefore, H.264 obtains broad applications in network streaming media.

AYS which also names “Audio and Video coding Standard” is the second generation source coding standard. Its intellectual property is owned by China. AVS has low implementation complexity and clear intellectual property. AVS can support existing streaming media system and can be applied widely in multimedia field.For H.264 coding standard, this dissertation analyzed the syntax and data organization format of RTP format and Annex B format, which are two file formats of H.264. Combined with streaming media transmission protocols RTSP/RTP/RTCP, a streaming media system supporting real-time transmission of H.264 video was developed and it achieved real-time play and download of streaming media data.

For the AVS coding-decoding standard, this paper implemented a streaming media system supporting AVS and it achieved streaming media download and real-time play. In a multi-function set-top-box, the physical connection may break down when a user watches a program and this can cause interruption of play and further affects user’s experience. In order to deal with this case, the dissertation analyzed the time mechanism in streaming media transmission and implemented a reconnection function through three steps of network broken detection, attempt to connect to network, continuous reception of data.The main research contents of this paper include the following aspects:

1. The principle of streaming media technology is analyzed and streaming media protocol stack is implemented; the streaming media protocol RTSP/RTP/RTCP and their inactivity principle is studied. We implementated a streaming media client based on embedded platform and the client constitutes a streaming media system with general streaming media server.

2. Researched the new generation video coding-decoding standard H.264 which is widely used in networks, analyzed the main file formats (including RTP format and Annex B format) in detail and studied the implementation of H.264 video transmission system based on RTP format and Annex B format.

3. Studied the second generation source coding standard AVS whose intellectual property is owned by China and analyzed its file organization format. Combined with streaming media technology, the paper did research on implementing video streaming media transmission system supporting AVS.

4. Aiming at the problem that physical connection suddenly breaks down when a user watches a program using a set-top-box, the paper studied and designed the reconnection function in set-top-box.Through research about several aspects in the above, we implemented streaming media protocol stack and embedded streaming media client and founded a basis for further research on streaming media technology. We implemented the reconnection function in set-top-box and streaming media transmission system based on H.264 and AVS, and provided a platform for studying H.264 and AVS streaming media transmission technology deeply.

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