為了要有效地滿足不同接收端的需求，一種新的視訊編碼技術產生，為可調式視訊編碼技術，不 同 於 傳 統 編 碼 技 術，可調式視訊編碼技術只要做一次編碼，即可產生一份符合不同接收端要求的位元串流(bit stream)；本文，在高速移動環境下，經由WiMAX網路，提出一個適應性SVC視訊分層演算法，首先，串流伺服器(Streaming Server)透過即時傳輸協定傳遞視訊資料給客戶端(StreamingClient)，然後，為了要偵測網路可用頻寬，客戶端收到資料後，計算封包掉落率與接收位元個數，並利用RTCP App Packet回傳統計資料，接下來，串流伺服器再根據回傳統計資料封包掉落率估算網路可用頻寬，最後，選擇適用於網路可用頻寬之視訊資料，因為改變傳送之視訊資料主要根據網路狀況， 故為一適應性串流傳輸系統。

In order to satisfy the requirement of different receivers, a new video coding scheme appears. That is Scalable Video Coding (SVC). Different from traditional coding scheme, SVC only encodes a bit stream once,
and the bit stream can be corresponded with the requirement of different receivers. In this paper, we propose an adaptive SVC layer switching algorithm through the dedicated Worldwide Interoperability for Microwave
Access (WiMAX) network at the high speed moving environment. At first, Streaming Server delivers video data over Real-time Transport Protocol (RTP). Then, for the sake of detecting available network bandwidth,
Streaming Client calculates packet loss rate as well as the number of receiving bytes after receiving RTP packets. Later, Streaming Client reports static information to Streaming Server. Next, Streaming Server can
estimate available network bandwidth according to static information such as packet loss rate. Finally,Streaming Server selects video data which are adapted to estimated network bandwidth. Our streaming system is also called an adaptive streaming system because video layer switching is based on network condition.