| People can see what happens in remote site using video monitor systems, such systems have been used more and more in lots of fields, and the scope of monitor system will be larger if the transmit network is a wirless network. Such wireless video monitor system can break through the restriction of geographical position.The technologies of this system include multimedia data processing, embedded system driver deveopment and multimedia data transmission. The system includes embedded system capture and encoding, wireless network transmission, decoding, displaying, providing media service and accessing media service. The system consists of development of capture site, server site and the browser.The browser which may be far away the server can sees the capture site.At present, Microsoft's DirectShow and Windows Media technologies are relatively important Multimedia processing technologies.We can process Multimedia data freely on Windows operating system. Hower, since other operating system such as Linux and Mac OS are used more and more, it is very necessary to bring forward a Multi-Platform Multimedia Processing Architecture. In this dessertation, I give a brief introduction to DirectShow and Windows Media technologies at first, and then extend the idea of DirectShow, put forward and design a Multi-Platform Multimedia Processing Architecture, named MPMA.The capture site of this system is based on Windows CE.NET embedded operating system. The video data is encoded into MPEG4video data using a MPEG4 chip GO7007SB which is provided by a American corporation WISChip.The chip is connected to ARM core embedded computer through USB interface. This dessertation describes the characteristics of Windows CE.NET USB device driver development and the development of this MPEG4 chip USB device driver in detail.Generally, the transmit protocol of Multimedia data is RTP/RTCP protocol, because this protocol can ensure the transmit quality of Multimedia data.This dessertation describes RTP/RTCP protocol in detail, and analyze the design idea of RTP/RTCP protocol stack. It also introduces how to use an opensource RTP/RTCP protocol stack JRTPLIB.The Server site is based on DirectShow technology. The application receives data from network and decodes them, and then the data is splitted into two ways. One is connected to Renderer Filter, the other provides Windows Media service. I have developed two Filters, one is MPEG4 Net Receiver Filter which receives data from network and sends the data to decoded Filter. Essentially, MPEG4 Net Receiver Filter is a Source Filter.The other Filter is WMV Encoder Filter which provides Windows Media service using MMS protocol. I have used Windows Media technology WMFS (Windows Media Format SDK) to encode the data into windows stream format in WMV Encoder Filter.At present, most video monitor system is based on C/S architecture, hower, there are lots of disadvantages of this architecture, the server site is usually a bottleneck in system.The dessertation bring forward a new monitor system which is based on P2P and SIP technology. P2P technology is used to overcome the shortages of C/S architecture system. SIP is a signaling protocol for Internet conferencing, telephony, presence, events notification and instant messaging. System with SIP is compatible with the existing system, and 3G network is using SIP as a protocol to provide IP multimedia service. On the research of P2P and SIPtechnology, I put forward a prototype of video monitor system based onthese technologies. |
PDF Full Text Request