An evaluation framework for 360-degree video compression

360-degree video is emerging as a new way of offering immersive visual experience. 360-degree video can be viewed on dedicated head mounted devices as well as on conventional 2D displays. Due to increased resolution to support wide field of view, efficient compression of 360-degree video becomes crucial. Whereas it is of significant interest to evaluate how different projection formats impact the compression efficiency of 360-degree video, a main technical challenge is that the input video is captured in a given native projection format, and that the native format has an obvious edge over other projection formats. In this paper, an evaluation framework is proposed to reduce the bias towards the native projection format when comparing different projection formats and their impact on 360-degree video compression. Additionally, a quality metric called area weighted spherical PSNR (AW-SPSNR) is proposed for objective 360-degree video quality evaluation. The proposed evaluation framework was included in the common test conditions defined for the exploration work of 360-degree video compression technologies under the Joint Video Exploration Team (JVET).