可適性視訊編碼(Scalable Video Coding；SVC)為H.264/AVC 影像編碼技術的延伸，除了原本H.264/AVC 的低位元輸出率、高抗錯性及網路友善性的優點，還加入了分層編碼的概念，提供了三種可調性：時間、空間及訊噪比可調性，可以依據網路的狀況和用戶端的裝置動態調整至至最適當的bitstream。 即使SVC 有分層的概念，但當SVC 在無線的環境傳輸時，因為無線的環境下頻寬的資源有限，且通道變化大，因為SVC 分層的特性使得每一層的碼率及重要性皆不相同，若在傳輸每一個Layer 皆採用相同的實體層設定，則較無法充份利用SVC 之特性進行傳輸。 因此，本文要探討的範圍在IEEE 802.16e Mobile WiMAX 的環境下，基於SVC 各層採用不同的實體層設定，如何針對訊噪比、傳輸速率及誤碼率之間選擇最適合該層的調變與編碼環境。 The Scalable Video Coding (SVC) is an extension of H.264/AVC. In addition to the advantage of original H.264/AVC with output of the low bit rate,high resistance of fault and network friendliness, it also owns the concept of layered coding, and offers three scalability: temporal, spatial and SNR which can be based on network conditions and client devices to dynamically adjust to the most appropriate bitstream. When the SVC transmitting in the wireless environment,because the bandwidth of the wireless environment is limited, and channel condition changes, the layered coding makes the SVC bit-rate and the importance of each layer are not the same if each layer in the transmission has the same PHY configuration. It is unable to take full advantage of the characteristics of SVC transmission. Here, we propose a mechanism based on ILA that lets PHY Layer configuration for each SVC layer to optimizing the transmission rate for each SVC layer.
