The Design And Implementation Of Video Sharing Module In Home Information Terminal

With the rapid development of computer network and multimedia, many videosharing system based on high performance server and personal computer have appeared,which meets people’s spiritual needs in some extent, but its mobility and costs havebecome an important obstacle of the continued development of it. However, As mobileinternet getting master and the performance of embedded platforms improving, theproblem can be solved easily in embedded video sharing system, and people can share theprogram at anytime and anywhere.With home multimedia entertainment as scenarios and a thorough discussion ofrelated techniques which comprise embedded graphics user interface, signaling control,audio&video processing, this paper designs and implements video sharing system basedon resource constrained but movable embedded platform. We choose Qt-Embedded toimplement a friendly user interface, besides, the remote control mouse is an important toolto manipulate user interface and input messages, we have handled it by a special way toimprove the user’s experience, user can interact with the terminal easily by manipulatingthe remote control, which results in signaling control message. On the side of signalingcontrol, this paper realized some extensions based on session description protocol to meetmore controlling needs, such as the negotiation of transmission bit-rate, video format andso on. After establishing a session in the use of SIP, we need to process the multimediadata by calling the audio&video processing module, which includes multimedia codecrealized by ffmpeg and transmission based on RTP. On the side of transmission, we haveoptimized the packing and unpacking of the data and added a priority queue for cache inthe receiver to deal with the jitter caused by the transmission delay, we also have handledthe problem of packets losing to enhance the robustness of the system. With the timestamp in RTP/RTCP, we implement an audio and video synchronization algorithm basedon the audio time stamp as the reference clock, at the same time, we also should pay moreattention to the synchronization in the encoding.Associate with characteristics of the embedded platform, this paper implements andtests the video sharing system, the test results shows it is easy to use, and can meet thevideo sharing requirements with a good real-time feather and high robustness.