Peer Upsampled Transform Domain Prediction for G-PCC

To meet the growing demand for point cloud compression, MPEG is developing a point cloud compression standard called as G-PCC. In G-PCC, upsampled transform domain prediction (UTDP) is used to improve attribute coding performance. However, only the attributes in the previous level can be used to predict the attributes of transform sub-blocks in UTDP, which limits the efficiency of UTDP. To address this limitation, we propose a method called peer-UTDP to improve UTDP by using peer neighbors in this paper. With peer-UTDP, attributes of co-plane or co-line peer neighbors in the level same as that of the transform sub-block can be used as prediction in the upsampling process. Experimental results show that our method outperforms G-PCC with an average coding gain of -5.1%, -5.4%, -5.1% and -1.4% under C1 condition, and -5.1%, -5.6%, -5.6% and -1.7% under C2 condition for Y, Cb, Cr and reflectance, respectively. The proposed peer-UTDP has been adopted by G-PCC.