Hybrid coding for animated polygonal meshes: combining delta and octree

A new hybrid coding method for compressing 3D animated sequences of geometric data is presented. It is based on the most common representation of the geometric data: polygonal meshes for each discrete frame in the animation sequence. The method utilizes a delta coding and an octree-based method. It can achieve higher compression ratios than the octree-only method or the delta-only coding method. In this hybrid method, both the octree approach and the delta coding approach are applied to each single frame in the animation sequence in parallel. The approach that generates the smaller encoded file size is chosen to encode the current frame. Given the same quality requirement, the hybrid coding method is much better than either single approach in terms of compression ratio.