Abstract: Recently, MPEG-4 is being formed to study very-low-bit-rate (VLBR) video coding for applications in videotelephony. In this paper, we propose a possible postprocessing technique for VLBR coding. In videophone applications, temporal subsampling is a simple technique which can be combined with other compression schemes to achieve very large compression ratio, so as to satisfy the VLBR requirement. As a result, object motions tend to be jerky and disturbing to the human eyes. To smooth out object motions, we propose a postprocessing technique, motion compensated temporal interpolation (MCTI), to increase the instantaneous decoder frame rate. In MCTI, block-based exhaustive motion search is used to establish temporal association between two reconstructed frames. Both forward and backward searches are used to account for uncovered and newly covered areas properly. With MCTI, we show that one or more frames can be interpolated with acceptable visual quality. After showing the feasibility of MCTI, we propose a fast algorithm FMCTI with reduced computation requirement and negligible performance degradation.!3
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