視訊壓縮標準H.265/HEVC是由JCT-VC (ISO/IEC MPEG和 ITU-TVCEG)所開發與制定，其編碼效率相較於過去的視訊壓縮標準H.264/AVC有大幅的提升，僅需約H.264/AVC之50%的位元率，即能達到與之相同的序列品質，然而還無法取代目前最普及的視訊壓縮標準H.264/AVC。此外，隨著硬體設備品質要求越來越高的情況下，例如電視的超高畫質序列(Ultra High Definition, UHD)等等，因此，H.264有效率地轉碼至HEVC編碼架構是目前探討的重要課題。 本論文探討優化H.264轉碼至HEVC的編碼架構，其中分為兩部分，第一部分為討論將原始的解析度序列進行H.264及HEVC編解碼，參考不同的量化參數配置、序列特性及實驗配置，決定經過H.264編解碼後的序列是否值得再進行HEVC轉碼；第二部分則改變輸入序列，將原始的解析度序列進行降取樣，接著由H.264及HEVC編解碼，之後再將輸出序列進行升取樣。實驗結果顯示，與序列由H.264進行編碼且量化參數為27的結果相比，序列以H.264進行編碼且量化參數為23轉碼至HEVC編碼且量化參數為27可以降低61%位元率，且PSNR仍然維持約38.12dB的序列品質。 ;The newest video compression standard H.265/HEVC is developed by JCT-VC (ISO / IEC MPEG and ITU-TVCEG), and it could achieve high coding efficiency compared with H.264/AVC. However, it could not replace H.264/AVC which is the most popular video compression currently. In addition, as the quality requirements of hardware devices become higher and higher, such as Ultra High Definition (UHD), and so on. Therefore, transcoding for H.264 to HEVC efficiently is currently important study . Efficient quantization parameter configuration for H.264-to-HEVC transcoding in this thesis to optimize the transcoding for H.264 to HEVC. The study is divided into two parts, the first part is coding and decoding the original sequence on H.264 and HEVC, and utilize different quantization parameters, image characteristics and experimental environment. Furthermore, the second part is to change the input sequence, up-sampling and down-sampling the original sequence, then followed by H.264 and HEVC codec. Experimental results show that the sequence which is encoded by H.264 and QP is 23 then transcode to HEVC and QP is 27 could reduce 61% bitrate and PSNR is still about 38.12 dB, compared to the sequence coded by H.264 and QP is 27.
