在XScale PXA255 實現嵌入式網路視訊電話

The Implementation of Video over IP on XScale PXA255

林建良(Jian-Liang Lin)

指導教授 ： 譚旦旭 ； 王永鐘

國立臺北科技大學/機電學院/機電整合研究所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00413

摘要

現今在網際網路技術蓬勃發展與普及的環境下，興起了各種多媒體服務，其中網路電話(VoIP)就是最熱門的應用項目之一。雖然網路電話技術已經非常純熟，但大部分僅限在個人電腦上使用或是透過電信業者的服務，對於單純地透過手持裝置在網路上進行對話的應用仍相當匱乏。
因此本論文研究主題為開發嵌入式網路視訊電話，使用XScale PXA255實驗版作為開發平台，在Windows CE作業系統環境下，利用軟體方式實現H.263視訊壓縮/解壓縮功能，並依照網路傳輸品質，適當調整影像壓縮比之參數值，以便在影像畫質與通話流暢度之間取得平衡。另一方面，受限於嵌入式系統有限的資源，我們在程式開發時，藉由非阻攔式的程式架構，讓目標平台發揮出最大的效能。本論文所發展的系統，經由實測驗證後，確實能達到點對點網路視訊電話的功能。

關鍵字

網路電話 ； 嵌入式平台 ； H.263視訊壓縮

並列摘要

With the rapid development and popularity of Internet, various multimedia services have come true today, where Video over IP(VoIP) is one of the most popular applications. Although the technique of VoIP is well developed, most usages are just stuck on PCs or through the services of telecommunication companies. There are still short of applications on handheld sets.
This study aims to develop an embedded video phone based on Windows CE. We employ XScale PXA255 evaluation board as the development platform and put the H.263 video encode/decode software on it. In accordance with the network transmission quality, we tune the compression parameters of H.263 to achieve better compromise between image quality and fluency. In addition, cause by limited resources that embedded system can release, we use the non-blocking program architecture while dealing with the application programs to ensure the embedded target board can accomplish its best performance. After implementation and verification, the system developed in this paper has been proved being able to carry out peer to peer video phone actually.

並列關鍵字

VoIP ； embedded system ； H.263

參考文獻

[1] W. Wang, S. C. Liew, V. O. K. Li, "Solutions to Performance Problems in VoIP Over a 802.11 Wireless LAN," IEEE Transactions On Vehicular Technology, vol. 54, no.1, January 2005, pp.366-384.

[5] 蔡志旺，PDA網路視訊電話，碩士論文，國立台北科技大學電機系，2006年7月。

[13] Charles Petzold, Programming Windows, Microsoft Press, 2000 Prentice-Hall, 1991.

[16] Draft ITU-T Recommendation , "H.263: Video Coding for Low Bit Rate Communication," ITU, May, 1996.

[20] Douglas Boling, Programming Microsoft Windows CE .NET 3rd, Microsoft Press.