隨著數位多媒體處理技術不斷進步，視訊應用不斷往高解析度、高幀率和高壓縮率的方向發展，為了使高畫質影片在有限的頻寬下傳輸，視訊編碼技術的效能扮演了重要的角色。最新一代視訊編碼標準HEVC(High Efficient Video Coding)與前一代視訊編碼標準(H.264/AVC)相較，在相同的編碼品質下可達到兩倍之壓縮率。在HEVC運用了編碼單元(Coding Unit, CU)、預測單位(Prediction Unit, PU) 以及轉換單位(Transform Unit, TU)等，在編碼過程中找出最佳的單元組合以獲得最好的編碼效能(率失真-成本)，但這個編碼過程的運算複雜度也大幅提升。為了應用在異質網路多使用者的環境中，基於HEVC編碼架構之延伸應用架構，可調式高效視訊編碼(Scalable Extension of the High Efficiency Video Coding, SHVC)，可以提供不同位元率的碼流，SHVC經過ㄧ次編碼便能得到能夠解碼出至少兩種以上的畫面率、解析度、品質的視訊，因此使不同的使用者能夠依據所使用的裝置之解析度或網路環境來接收適當的視訊品質。SHVC編碼過程中同樣需要處理CU、PU、和TU等單元的最佳組合之決定程序。因此有效運用SHVC層間關聯性以降低運算複雜度也是很重要的研究議題。本篇論文提出了兩種快速編碼方法：快速CU深度決策於增強層、快速PU模式決策於增強層。方法一為利用基礎層同位置CU的深度來決定增強層當前CU深度的測試範圍，可減少約47.59%的增強層編碼時間；方法二為利用空間性、時間性、層間性參考PU來預測當前區塊的複雜度，進而決定需要測試的預測模式，並提前決定是否為SKIP模式，跳過接下的模式與深度不測試，此法可減少58.43%的增強層編碼時間。實驗結果顯示將兩種方法結合在一起，平均能減少70.52%的增強層編碼時間。

With the advance of digital media processing technology, multimedia processing platforms have been developed toward higher resolution and framerate applications. The new video coding standard, High Efficiency Video Coding (H.265/HEVC), can provide twice the compression ratio under the same encoded quality, as compared to the previous one, H.264/AVC. In the HEVC, it utilizes Coding Unit (CU), Prediction Unit (PU) and Transform Unit (TU) to perform motion estimation/compensation and entropy coding for efficient video coding, i.e., best rate-distortion cost. However, the time complexity of this high efficient video coding is very high, as compared to previous ones. The extended application format of HEVC, scalable HEVC (SHVC), has been developed to serve multi-users with heterogeneous network and devices. The SHVC can provide different bitrate, resolution, or quality formats of the same video through the one-time encoding process. As the SHVC is developed based on the HEVC, its time complexity is high and has to be reduced for practical applications. In the SHVC, it has to select one best encoding mode, from different CUs, Pus and Tus, to achieve best RD-cost encoding. In this research, we proposed to utilize two fast encoding schemes to speed up the SHVC encoding process. (1) We utilized the encoding depth information of the co-located CU of the base layer to reduce the range of determining the current CU coding depth of the enhancement layer. It can reduce 47.59% of encoding time for the enhancement layer video; (2) We utilized the correlation between spatial, temporal and inter-layer PUs to predict the complexity of the current PU, which can reduce the PU mode decision operation steps. It can also be used to determine whether to SKIP or not to eliminate unnecessary processing steps. It can reduce 58.43% of time to encode enhancement layer video. Experiments showed that the overall encoding time can be reduced 70.52% processing time when both schemes are adopted by the SHVC.

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