The Research Of IP Video Phone's Video Encoder And Rate Control

IP video phone provides face to face communication service and is a hopeful product. It is not only fit for the family life, but also widely applied in various business affairs, long-distance teaching, secret monitor, hospital nurse, medical treatment , science research and other fields. Now with the developing of modern science and technology and the improvement of living level, the technology and the finance status limits are overcomed and the time of developing video phone is coming. It was well known that various communication companys presented lots of hospitals video phones in time when sars arised suddenly, which played an important role in contributing to the overcoming of the disaster.So we design a video phone system based on H.323 and Trimedia TM1300 DSP. H.323 is the standard about multimedia communication released by ITU-T. TM1300 including a very powerful, general-purpose VLIW processor core (the DSPCPU) that coordinates all on-chip activities is a media processor for high-performance multimedia applications that deal with high-quality video and audio. The DSPCPU implements a 32-bit linear address space and 128, fully general-purpose 32-bit registers. The video phone system designed by us is mainly the real-time implement of A-V codec the implement of H.323 protocol stack and the implement of the network communication protocol for example PPPoE SMTP and POP3 etc. So we not only ensure that the QoS of the A-V codec's datum, but also develop the increment services for example E-mail system and browser etc.The paper will emphasis on the graft and realization of the internet protocols H.263 video codec rate control algorithms for video encoder and optimization methods of the codec based on TM1300. H.323 SIP, H.264 and pSOS+ are also simply introduced. In the first chapter, the developping history and foreground of IP video phone and the system framework of the video phone including hardware and software framework are introduced. Then the research work is also introduced in this chapter. In the next chapter, H.323 SIP the difference of H.323 and SIP are introduced. In the third chapter, the graft of TCP/IP in OpenBSD on pSOS+ and the realization of the internet protocols including PPPoE PPP SMTP POP3 IMAP DNS DHCP, embedded WEB server and how to estimate network state used by RTP/RTCP are introduced. In the fourth chapter, firstly H.261 , H.263 H.263+ standards and their differences are introduced. Secondly the improved H.264 standard and the performance comparison of the H.263 and H.264 are introduced. In the fifth chapter, some optimization methods about program structure and optimization methods based on TM1300 are introduced. In the sixth chapter, the research of rate control methods which is the most difficult in my study is introduced.