Zerotree Coding of Subdivision Wavelet Coefficients in Dynamic Time-Varying Meshes

In this paper, we propose a complete system that
enables us to add the desirable feature of progressive coding with
quality scalability of the mesh geometry, to the current state-
of-the art method for dynamic time-varying mesh compression
– MPEG’s Video-based Dynamic Mesh Coding (V-DMC). In
particular, we propose an alternative method for encoding the
subdivision wavelet coefficients in V-DMC, using a mesh-based
zerotree coding approach. The proposed method works directly
in the native 3D mesh space and it allows us to identify
parent-child relationships between the wavelet coefficients across
different subdivision levels, which can be used to achieve an
efficient and versatile coding mechanism. We demonstrate that,
given a starting base mesh, a target subdivision surface and
the desired maximum number of zerotree passes, our system
produces an elegant and visually attractive lossy-to-lossless mesh
geometry reconstruction with no further intervention from the
user. Moreover, lossless coefficient encoding with our approach
is shown to require almost the same bitrate as the default HEVC
and the optional arithmetic coding methods in V-DMC, but our
approach provides several levels of quality resolution within that
bitrate amount while the current solutions encode a single quality
resolution level only. To the best of our knowledge, this is the
first time that a zerotree-based method has been proposed and
demonstrated to work for the compression of dynamic time-
varying meshes, and the first time that such an embedded quality-
scalable approach has been designed for the V-DMC framework.