| Summary: | 碩士 === 國立清華大學 === 資訊工程學系 === 95 === With the development of internet, video communication becomes an important application in human’s life. People can use PC, DTV, and even mobile phone to watch video programs over IP or wireless network. H.264/AVC (called H.264 as well) is a new standard made by ITU-T with high entropy rate and its bit stream is very suitable for video communication.
However, in a network, especially in a wireless network, transmission error is inevitable so that packet loss and bit error occur very often. It is impossible to ask the sender to resend packets in the video communication’s environment because the video sequence should be played in real time. At such situation, we have to adapt a method to conceal those errors in decoder instead of asking sender to resend packets. H.264 handles this problem by taking use of error resilience tools on encoder and error concealment algorithms on decoder so that the receiver can use correct regions to reconstruct the lost regions. The main topic to be discussed in this paper is error concealment on the decoder side.
There is a default error concealment algorithm in H.264 standard, but the performance is not so good. In this paper, we will propose a refined error concealment algorithm. In I-frame, we improved the interpolation algorithm and use data hiding technique in some condition to make the performance be better. And in P-frame, we hybrid “Temporal Error Concealment” (TEC) and “Spatial Error Concealment” (SEC) to introduce our proposed method in I-frame into P-frame. The experience results show that our method can enhance the performance on both human vision system and PSNR. Our proposed method is suitable for the error concealment in H.246 video communication over wireless network.
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