  Point cloud based 3D visual representation is becoming popular due to its
ability to exhibit the real world in a more comprehensive and immersive way.
However, under a limited network bandwidth, it is very challenging to
communicate this kind of media due to its huge data volume. Therefore, the MPEG
have launched the standardization for point cloud compression (PCC), and
proposed three model categories, i.e., TMC1, TMC2, and TMC3. Because the 3D
geometry compression methods of TMC1 and TMC3 are similar, TMC1 and TMC3 are
further merged into a new platform namely TMC13. In this paper, we first
introduce some basic technologies that are usually used in 3D point cloud
compression, then review the encoder architectures of these test models in
detail, and finally analyze their rate distortion performance as well as
complexity quantitatively for different cases (i.e., lossless geometry and
lossless color, lossless geometry and lossy color, lossy geometry and lossy
color) by using 16 benchmark 3D point clouds that are recommended by MPEG.
Experimental results demonstrate that the coding efficiency of TMC2 is the best
on average (especially for lossy geometry and lossy color compression) for
dense point clouds while TMC13 achieves the optimal coding performance for
sparse and noisy point clouds with lower time complexity.
