1. A method of video compression, the method comprising: providing an input sequence of frames each including picture regions; and processing the input sequence of frames to generate an output sequence of frames including referenceable frames and at least one bi-directionally predicted frame, wherein: the processing comprises determining unequal weights, the unequal weights being used to interpolate pixel values of at least one picture region of at least one bi-directionally predicted frame by reference to two or more referenceable frames in the input sequence, the frames comprise chroma signal components and luminance signal components, the processing comprises processing the chroma signal components of the frames differently from processing the luminance signal components of the frames, and the unequal weights are utilized for pixel luminance values and pixel chroma values of at least the one picture region.