A study on the use of vector rational interpolation for the estimation of erroneously received motion fields of MPEG-2 predictively coded frames is undertaken in this paper, aiming further at error concealment (EC). Various rational interpolation schemes have been investigated, some of which are applied to different interpolation directions. One scheme additionally uses the boundary matching error and another one attempts to locate the direction of minimal/maximal change in the local motion field neighborhood. Another one further adopts bilinear interpolation principles, whereas a last one additionally exploits available coding mode information. The methods present temporal EC methods for predictively coded frames or frames for which motion information pre-exists in the video bitstream. Their main advantages are their capability to adapt their behavior with respect to neighboring motion information, by switching from linear to nonlinear behavior, and their real-time implementation capabilities, enabling them for real-time decoding applications. They are easily embedded in the decoder model to achieve concealment along with decoding and avoid post-processing delays. Their performance proves to be satisfactory for packet error rates up to 2% and for video sequences with different content and motion characteristics and surpass that of other state-of-the-art temporal concealment methods that also attempt to estimate unavailable motion information and perform concealment afterwards.
['Sofia Tsekeridou', 'Faouzi Alaya Cheikh', 'Moncef Gabbouj', 'Ioannis Pitas']
Vector rational interpolation schemes for erroneous motion field estimation applied to MPEG-2 error concealment