An extension of conventional block motion compensation (BMC), overlapped block motion compensation (OBMC) has been shown to reduce residual errors and blocking effects in motion-compensated video. However, the overlap creates a noncausal spatial dependence between blocks and complicates motion estimation (ME) for OBMC. Iterative methods have traditionally been employed for overlapped block motion estimation (OBME). For compression, the rate for the motion vector field (MVF) may also be constrained. This work considers several rate-constrained OBME algorithms, both iterative and noniterative. Experiments demonstrate that a simple raster-scan algorithm is effective as a suboptimal, noniterative solution, with comparable or better rate-distortion performance and computational complexity than iterative OBME algorithms. Depending on the application, either this method or a simple block-matching algorithm plus iteration are the most attractive of the tested OBME schemes.

For many video compression systems, overlapped block motion compensation (OBMC) provides an effective extension of traditional block MC (BMC). However, because OBMC causes noncausal spatial interaction between blocks, iterative methods have typically been used for motion estimation (ME) for OBMC. For compression purposes, the rate for the motion vector field may also be constrained. This paper considers several rate-constrained ME methods for OBMC. Experiments demonstrate that a simple raster-scan algorithm is effective as a suboptimal non-iterative solution, with better rate-distortion performance and equal or lower computational complexity than several iterative methods.

At low bit rates, most video coders drop frames from the original video. Motion-compensated interpolation (MCI) requires no additional bandwidth and can interpolate the missing frames. Existing MCI methods, developed for uncompressed video, are computationally demanding and require additional motion estimation (ME). By exploiting the motion field already present in the coded video, the MCI algorithms proposed in this paper eliminate or reduce extra ME with negligible performance loss. The algorithms are applied to original and coded video to verify their usefulness.