Consecutive corrupted MBs or slice errors are commonly seen in modern video transmission systems. Temporal error concealment is an effective approach to reduce the impact of errors. Conventional temporal error concealment techniques recover slice errors on a MB basis. We propose a new novel temporal scheme for slice error concealment based on a size-adaptive region basis. Size-adaptive region boundary matching can significantly reduce the misalignments or side mismatches that are commonly seen in MB-based approaches. Instead of using MSE or MAE as the matching criteria, We propose a matching criterion based on structural similarity (SSIM). Our proposed matching criterion can achieve better structural alignments and better visual perceptual quality. We also propose a method to detect motion vector outliers at the last stage of the error concealment scheme, which can further improve the visual quality of the concealed videos. Our proposed scheme conceals slice errors with good accuracy...