當前的新視頻設備和應用需要有效的壓縮方法。在過去的幾年中，通過不同類型的網絡將視頻流式傳輸到不同的設備已經大大增加，設備範圍從電視到智能電話以及從有線網絡到無線網絡的網絡都活用了Long Term Evolution Advanced (LTE Advanced)。無線電視和娛樂產業的快速發展增加了對高清晰度，高幀率視頻應用的需求。由於H.264 / AVC主流壓縮標準存在缺陷，在2013年4月，德國德累斯頓舉行的JCT-VT會議定義了新一代視頻編碼標準 - 高效視頻編碼（HEVC）。 HEVC旨在將視頻的壓縮效率提高一倍，這意味著在相同的重建質量下，比特率將降低50％。然而，當通過IP網絡或無線移動網絡傳輸視頻數據時，總是會發生隨機錯誤和視頻數據損失。事實上HEVC仍然採用與H.264中相同的幀間和幀內預測機制，高壓縮視頻數據易於出現通道錯誤。有時即使很少的錯誤也可能對視頻數據的重建質量產生嚴重影響。本文仔細分析了HEVC的特點，並進一步研究了後解碼過程中的錯誤隱藏技術。然後提出了考慮HEVC特徵的錯誤隱藏算法。針對容易出錯的視頻傳輸信道，提出了一種利用線性插值的擴展混合錯誤隱藏算法。在所提出的混合算法中，首先採用選擇性運動場內插（SMFI）來隱藏錯誤的LCU。然後使用空間和時間邊界匹配的誤差來檢查SMFI是否正確地隱藏了錯誤的宏塊。如果不正確地重建時間恢復的宏塊，則使用線性插值的空間錯誤隱藏來隱藏損壞的宏塊而不是SMFI。所提出的混合演算法在空間和時間錯誤隱藏上採用線性插值法。;Abstract The current and new video devices and applications require an efficient compression methods. Streaming of video to different devices over different types of networks has substantially increased during the past few years, with devices ranging from connected televisions to smart-phones and networks ranging from wired networks to wireless networks making use of Long Term Evolution Advanced (LTE Advanced). The rapid development of radio television and video entertainment industries has increase the demand for high definition, high frame rate video applications. As the H.264/AVC mainstream compression standard has its deficiency, In April 2013, JCT-VT meeting held in Dresden, Germany, defined the new generation video coding standard called High Efficiency Video Coding (HEVC). HEVC is aimed to double the compression efficiency of videos, which means that the bitrate will be reduced by 50 percent under the same reconstruction quality. However, when video data are transmitted through IP networks or wireless mobile networks, random error and loss of video data always occur. The fact that HEVC still adopts the same inter and intra frame prediction mechanism as in H.264, high compressed video data are prone to channel errors. Sometimes even few errors may have serious impact on the reconstruction quality of video data. This paper closely analyses the characters of HEVC, and further studies error concealment technology in the post-decoding process. Then it proposes error concealment algorithms which take the characters of HEVC into account. An extended hybrid error concealment algorithm using linear interpolation for error-prone video transmission channel is been suggested. In the proposed hybrid algorithm, the selective motion field interpolation (SMFI) is first employed to conceal the erroneous LCU. The spatial and temporal boundary-matched errors are then used to check whether the SMFI conceals the erroneous macroblock properly. If the temporally recovered macroblock is reconstructed incorrectly, the spatial error concealment using linear interpolation is employed to conceal the damaged macroblock instead of SMFI. The proposed hybrid algorithm employs the linear interpolation on both spatial and temporal error concealment.
