Motion modelling plays a central role in video compression. This role is even more critical in highly textured video sequences, whereby a small error can produce large residuals that are costly to compress. While the translational motion model employed by existing coding standards, such as HEVC, is sufficient in most cases, using higher order models is beneficial; for this reason, the upcoming video coding standard, VVC, employs a 4-parameter affine model. In this work, we explore the use of the discrete cosine basis for motion modelling in highly textured video sequences, and show that this is beneficial. In particular, we use a single high-order model to describe a frame's motion; we employ this motion to produce an extra prediction reference, which is added to the HEVC list of references. Experimental results show that a median delta bit rate of 4.44% is achievable over conventional HEVC if this extra reference frame is used in addition to the temporal references offered by HEVC.