螢幕內容分享服務隨著Apple airplay推出後，成為熱門影音分享服務。另一個新興雲端互動 式螢幕分享服務亦透過網際網路將遠端伺服器執行的螢幕畫面分享至使用者，讓使用者可透過互 動介面操控遠端伺服器，此應用包括雲端信箱、雲端遊戲、雲端智慧家庭、Remote Play、Thin Client 及遠端桌面等。針對上述應用，國際視訊標準組織ISO/IEC MPEG與ITU-T共同成立了JCT-VC團 隊，著手制定新的高效能螢幕內容編碼標準。本論文會先介紹由微軟所提出的一個全新的編碼工 具：調色盤編碼技術(palette-based coding，PBC)，其概念是搜尋一個或多個主要顏色來代表這個 編碼單元(coding unit，CU)內的畫面，並利用這些顏色所對應到的顏色索引(color index)來對編碼 單元內的每一畫素進行索引編號，最終再針對這些顏色索引去進行無失真編碼。而為了提升調色 盤編碼技術之效能，本論文提出一種利用可變長度片段複製的索引編碼技術，讓編碼器可以彈性 的選擇一可變長度之索引片段，從已解碼之顏色索引進行複製編碼，達到更高的壓縮效能。我們 所提出的索引編碼技術，在相同的視覺品質下，可達到0.6%的壓縮率。

Screen sharing services have received extensive attention since apple Inc. announced screen mirroring functionality, called airplay. Besides, there are also many envisioned applications of screen sharing, such as cloud mailbox, cloud gamming, cloud play, remote play, thin -client, remote desktop control and so on. For meeting the requirements of emerging applications, ISO/IEC MPEG and ITU-T are jointly working on making a high efficiency screen content coding standard (SCC). This article will first introduce a palette-based coding (PBC) proposed by Microsoft. The concept of PBC is to search one or more major colors to represent the pixels inside a coding unit (CU), and to use the color indexes of the major colors to sequentially code each pixel in the current CU. To improve the coding performance, this article proposes a variable-length segment copy technique for compressing index map of palette coding in SCC. The results show that the proposed technique outperforms current standard one in terms of coding gain under the same visual qualit y.