Skype主要提供了三種的服務型態：語音、短訊息、以及新增的影像視訊(Video Conference)服務，其中短訊息對於即時性(Real Time)的要求性不高，而在語音及影像視訊都需要有嚴格的網路服務品質(Quality of Service, QoS)控管，才能保証其接收品質。近年來己有許多針對Skype語音品質的研究，但是在影像視訊品質上尚未討論文獻。
本論文中，我們提出量測Skype影像的方法，並針對Skype直接連線模式(Direct Mode)進行量測。在此模擬環境中本論文利用螢幕側錄的方式將接收端的影像記錄下來，並與傳送端的影像比較峰值信號雜訊比(Peak Signal to Noise Ratios, PSNR)值來衡量其影像品質，同時利用網路損傷模擬器(Network Impairment Emulator)，模擬封包經網路傳遞後的損傷進行量測。相關的模擬的結果除了可以了解Skype在各種網路環境下的影像品質外，亦可提供給Skype設計者參考進而改進其影像品質。

Skype provides three fundamental service types: voice, short message, and additional video conference. The real-time service is not highly demandable for short message, but both the voice and video conference require strict network quality of service (QoS) to guarantee the receiving quality. Recently, many researches are delivered for Skype; however, they focus on voice quality and no relative research on video quality.
In this thesis, it provides the method to measure the Skype video quality, especially in direct mode for Skype connection scenario. This work measures the video quality by comparing the peak signal to noise ratio (PSNR) between the transmitting video and receiving video which is monitored and recorded in simulation environment. This work also uses the network impairment emulator to simulate the packet impairment though the network transmission. Relative simulation results could realize the video quality of Skype in various network environment, and also provides a reference scheme for Skype designer to improve the video quality.

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