| Subject of this article is from project 60702049 supported by National Key Science and Technology (NSFC).As the rapid development of computer network, communication and multimedia technology, video communications have become one of the main applications in the field of Information and Communication. Video communications require more stringent real-time and a larger bandwidth. High compression rate coding technologies used in most video applications cause the encoded code stream more sensitive to the transmission error. So it is very necessary to enhance the capability of transmission error resilience and error recovery in video communications. This is also the current research focus in multimedia communications.This paper mainly focuses on the decoder temporal error concealment technology based on the analysis of the H.264 and related existing error resilience technologies. Except introducing the details of existing error resilient tools in H.264 and the implementation of error concealment scheme in JM model, this paper proposes a Directional Temporal Boundary Match Algorithm (DTBMA) based on the summary of the existing temporal error concealment algorithms. This algorithm obtains recovered motion vector (MV) according to the direction which has minimum difference between recovered boundary pixels and neighbor pixels in reference frame firstly. Besides of above improved method, this paper also proposed a Variable Block Error Concealment (VBEC) method which first decides proper block size of the lost macro-block according to the situation of block size of neighboring macro-block, and then reconstructs the lost macro-block utilizing DTBMA above. This paper does the simulation of proposed algorithms applied in different video sequence using JM15.1 test model. The results show that the proposed algorithm increases PSNR and improves subjective video quality compared with conventional temporal error concealment algorithms in the case of no significant increase in time complexity. |
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