Spatial-Temporal Error Concealment Scheme for Intra-coded Frames

Abstract

Error concealment with good restored video quality and low computational cost is significantly required for video streams transmitted in error-prone channels, especially for real-time applications. An efficient error concealment scheme for intra-frame is proposed. Spatial circular interpolation method is used to prevent the accumulation of prediction error. Meanwhile the motion vectors surrounding the damaged MB are used when all the adjacent blocks are error to improve the effect of error concealment. The experimental results indicate that compared to the spatial error concealment algorithm in H.264, the proposed scheme can restore more texture information and improve the quality both subjectively and objectively greatly.Keywords Error Concealment; Spatial-temporal; Intra-coded Frame . INTRODUCTIONThe emerging video coding standard H.264, which is jointly developed by ITU-T and MPEG, provides state-of-the-art video coding technique and the main goals of this standard are enhanced compression performance and provision of a network friendly video representation [1]. However it is sensitive to the transmission errors. Due to the high-efficiently predictive coding and the variable length entropy coding, errors will not only corrupt the current frame but also propagate to the succeeding frames [2].There are four main strategies for eliminating the image quality degradation effect by transmission errors [3], including (1) the channel coding strategy, (2) the error resilient (preprocessing) strategy, (3) the encoder-decoder interactive error control strategy, and (4) the error concealment (post processing) strategy.In the error concealment (post processing) strategy, based on the redundancy information inherent in neighboring pixels and the constraints on compressed video data, transmission errors can be directly corrected or concealed without changing the encoder or embedding redundant bits or set up a feedback channel from the decoder to the encoder like the other three strategies, so it becomes more and more popular in video transmission.In this research, we focus on the error concealment techniques for intra-coded frames. Error concealment is a non-normative feature in H.264, test model. The objective is to provide a basic level of error resiliency for the decoder. Weighted picture value averaging for intra pictures and boundary-matching based motion vector recovery for inter pictures [4] were the two main ideas customized for the error concealment algorithm implemented in H.264 [5].In the past a few years, great efforts have been made to improve the concealment techniques for intra-coded frames [6,7]. Spatial error concealment algorithm utilizing directional decision and intra-prediction, has been proposed to improve the capability of recovering edges with relatively lower computational complexity [8]. However, the effectiveness of these spatial error concealment techniques based on the information of edge detection is probably dependent on the accuracy of the edge detection algorithms. On the other hand, the edge...