Numerous MCFI methods have been proposed to increase the frame rate in the past ten years. However, these methods usually focus on how to double the frame rate and involve complex computation, complicated time-consuming iterations, and are difficult to implement for real-time High-Definition (HD) videos. In this paper, a fast one-pass processing method is proposed for high Motion Compensated Frame Interpolation in HD videos. This approach is based on our basic MCFI scheme, slightly increases complexity, and achieves 4x Frame Rate Up Conversion. Relative Motion Estimation (RME) is also proposed to enhance the accuracy of motion search.