Optimal Camera Placement for 6 Degree-of-Freedom Immersive Video Streaming Without Accessing 3D Scenes

Abstract

We consider a 6 Degree-of-Freedom (6DoF) immersive video streaming eco-system, which is composed of content creators, cloud service providers, and Head-Mounted Display (HMD) users. To avoid intellectual property leakage, content providers only offer rendering and query access, which significantly complicates the problem of placing source cameras to maximize the synthesized quality for multiple 6DoF HMD viewers. We address three key challenges: extremely large search space, nonlinear synthesized quality models, and computationally-intensive numerical algorithms. Three algorithm variants: C1G, C2G, and C2I, have been proposed. The first one employs a first-order coverage model, while the last two employ a second-order coverage model; moreover, the first two adopt a greedy method, while the last one adopts an Integer Programming (IP) solver. We implement a prototype system and carry out evaluations based on a real dataset consisting of 16 subjects collected by us. Our evaluation results reveal that, with 16 source cameras, our algorithm: (i) outperforms the baseline one by at least 2.37 dB in PSNR, 0.05 in SSIM, and 10.84 in VMAF and (ii) achieves an optimality gap as small as 1.00 dB in PSNR, 0.01 in SSIM, and 2.30 in VMAF.