Application Of H.264 Standard In H.323 System

With the rapid development of modern communications technology, Internet and computer technology, IP-based network of H.323 video conferencing system has been increasingly being widely used, and at the same time, as the video coding standard of constantly are updated, its advantages have been more and more familiar and various aspects of application have been received. On the basis of analyzing protocal H.323 and the latest video coding standard H.264, one way to transmit H.264 video in Openh323+ is studied and experimental results are given in this thesis.In this thesis, careful study of video coding standard H.264 was done. The new technologies adopted by H.264, such as the inta-frame encoding, loop filtering, entropy coding, quantify and transform, were introduced. The advantge of using H.264 in H.323 system was presented. And a more detailed analysis of The H.323 protocol architecture was given. The H.323 communications transmission control protocol, audio and video transmissio H.323 entities, as well as H.323 call flow were discussed. And the protocol stack OpenH323+ was metioned.As a new video coding standard, there are a lot of differences between H.264 and standards in the past, such as architecture. So many issues of the application of H.264 in H.323 system lead to necessary supplement and amende of H.323. Based on the new characteristics of the H.241 protocal which was added to the H.32x series of agreements by ITU-T, the design of H.264 video trassmition over H.323 system was proposed and implemented whith good experimental results. Through using different video coding standards, such as H.261, H.263, H.264, the conclusion that H.264 video coding standard has better quality of video transmission than H.261 and H.263 in the complex multi-threaded environment was achieved. The good image reconstruction quality and continuous movement screen obtained through experiment completely meet the requirements of real-time video communications in the IP network.