Research On Error Hiding Technology Based On HEVC

As the terminal processing capacity is improving and the demand for ultra-high definition video continues to increase, video applications are developing very fast in order to gain high definition and high compression rate. The widely used video coding standard H.264/AVC(Advanced Video Coding) is not able to meet the current needs of users. HEVC(High Efficiency Video Coding), which is a new generation of video coding standard, is aimed at doubled compression efficiency than before. Compared with H.264/AVC, when at the same picture quality, HEVC could reduce the bit rate by 50%. When the encoded video stream is transmitting in the network, burst packet loss and random error is inevitable. However, HEVC stream rarely has redundant information when at high rate of compression and there is a strong correlation between the coding streams, even less error in the case would lead to worsening the quality of the video, so it is necessary to study the error control technology of HEVC. Based on the sufficient analysis the features of the new generation video coding standard HEVC, this paper is focused on the study of error concealment techniques of the post-processing of decoder. Two suitable error concealment algorithms for HEVC have been proposed, and the main research work includes:1. Error concealment based on block segmentation. In the scheme, considering the partitioning of decoding block, the error concealment could be conducted separately. Due to the current decoding frame is similar with the reference frame, the segmentation information of co-located block can be used to replace segmentation information of currently missing segment block: Firstly, the block segmentation information of the co-located block of the lost block should be obtained; Secondly, after using motion vector extrapolation to obtain the lost-block’s motion vector, according to the segmentation parameter information of collocated block, motion vector optimization can be done among these segmentation block which boundary dimensions are less than 8; Finally, use the motion vector that has been optimized to do the error concealment, and experiments are carried out to verify this method. The result is that, compared with the direct recovery of decoding block, this method improves the effect of image restoration, which may have a positive influence on the error recovery.2. Error concealment based on block merging. In this scheme, segmentation information of the current lost block could be predicted according to the correlation of image coding residual energy and block segmentation, and the residual energy of the reference frame of the current frame: Firstly, the block segmentation information of the co-located block of the lost block should be obtained; Secondly, calculate residual energy of each 4×4 block, and compare with the preset threshold to determine the energy correlation; Finally, merge the blocks which have a consistent correlation between adjacent blocks, then conduct the error concealment. The experimental results show that, this scheme can solve the problem of HEVC in the recovery of large size code blocks. Compared with the existing HEVC error concealment scheme, this method has a superior recovery result.