True motion vectors for robust video transmission

In this paper, we make use of true motion vectors for better error concealment. Error concealment in video is intended to recover the loss due to channel noise by utilizing available picture information. In our work, we do not change the syntax and thus no additional bits are required. This work focuses on improving the error concealment with transmitted true motion vectors. That is, we propose a `true' motion estimation at the encoder while using a post-processing error concealment scheme that exploits motion interpolation at the decoder. Given the location of the lost regions and various temporal error concealment techniques, we demonstrate that our true motion vectors perform better than the motion vectors found by minimal-residue block-matching. Additionally, we propose a new error concealment technique that improves reconstruction quality when the previous frame has been heavily damaged. It has been observed that in the case of a heavily damaged frame, better predictions can be made from the past reference frame, rather than the current reference frame which is damaged. This is accomplished by extrapolating the decoded motion vectors so that they correspond to the past reference frame.