H.264/AVC是目前最先進的視訊壓縮標準且比起先前的標準提供了更高品質的壓縮效率。 然而在達到更高品質的壓縮效率的同時，H.264/AVC變得越來越複雜而且必須花費更高的計算複雜度。 若我們使用純軟體來實作H.264/AVC編碼器，編碼時間太慢是一個非常嚴重的問題。 此外隨著科技的進步，多核心系統已經迅速的被發展而且被應用在許多領域來增進系統效能。 在本論文當中，我們提出了兩個在多核心系統下的H.264/AVC平行編碼演算法來增進編碼的效能。 首先為了不使編碼器降低影像品質，我們提出了一個在macroblock層級的平行演算法來實作H.264/AVC編碼器，我們稱之為PMB演算法。 然而在PMB演算法中會有相當嚴重的資料通訊問題導致大幅降低平行的效能，因此我們提出了一個PMBG演算法來解決PMB演算法的缺點。 在PMBG演算法中我們定義了一個macroblock group為許多相鄰的macroblocks所組合而成並且提出了一個在macroblock group層級的平行演算法來實作H.264/AVC編碼器。 PMBG演算法能大大的舒緩PMB演算法所產生的資料通訊問題，它能夠大幅降低到記憶體取回資料的次數。 實驗數據顯示比起循序演算法JM 12.2，我們的平行PMB和PMBG演算法在四核心處理器下能達到至少3.09倍的加速且能保證與JM 12.2有相同的影像品質。

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