Enhancing Displacement Representation in the V-DMC Encoding Framework

The Moving Picture Experts Group (MPEG) is developing a new generation of the mesh coding standard, called Video-based Dynamic Mesh Coding (V-DMC). This standard represents a dense original mesh using a sparser base mesh, combined with a subdivision scheme and a set of displacement vectors that indicate the disparities between the subdivided base mesh and the deformed mesh, which approximates the original mesh. However, the lossy compression of the base mesh introduces displacement biases. Moreover, the one-dimensional encoding of these vectors, while saving bits, also leads to a loss of displacement information. In this paper, we propose a modified encoding framework to enhance the representation of displacement, thereby correcting biases and reducing information loss. Our method involves post-deformation to ensure the deformed mesh aligns with the reconstructed base mesh. Furthermore, by optimizing the deformed mesh corresponding to the reconstructed base mesh, more information is preserved in the encoded displacements, thus improving the quality of the reconstructed mesh. Experimental results show significant BD-rate gains over the V-DMC test model version 8.0, leading to its adoption in the V-DMC test model version 9.0.