360° monoscopic (mono) video is the most typical and basic form of stitched panoramic video. Usually it is captured from multiple cameras and then stitched together into a single panoramic video in a variety of video editing tools. 360° mono works well in VR, but only supports three degrees of freedom ( 3DoF). 360° mono does not support stereo, so there is no sense of 3D or parallax; the same video is delivered for both left and right eyes. Stitching artifacts between camera views are often visible. 360° mono video is low on the scale of immersive as it lacks visual cues like parallax, or view dependent reflections / specular highlights. 360° mono is the most common type of VR content found on YouTube and Facebook
360°stereoscopic (stereo) is typically captured with multiple pairs of left/right video cameras. The separate left and right video captures are stitched into a pair of panoramic videos for VR. The left and right channels are delivered either side by side, or over / under for each frame of video. Stereo 360° provides 3DoF with functional stereo for a 3D effect at the horizon where the camera pairs used to capture the original content were placed, but the stereo effect diminishes between those camera views, or when you look up/down or roll your head off the horizon line. There is a perception of depth and 3D for objects close to the viewer, however there are no immersive visual cues like parallax, reflections or specular highlights. As with 360° mono, stitching artifacts are often visible, and are much harder to eliminate. 360° stereo can be found in some online content, but is more common on dedicated VR systems like Samsung GearVR, Oculus Rift and HTC Vive.
Omnistereo is an advanced form of 360° stereo video. Omnistereo relies on a computational process that produces a series of vertical image slices (strips) from multiple camera views which are spliced together to produce left eye and right eye video channels for any view along the horizon. There are no stitching artifacts, and a greater number of narrow strips produce smoother omnistereo video and better stereo perception. The stereo effect is good when viewed along the horizon, however the effect diminishes when the viewer looks up/down and breaks when they roll their head. Omnistereo is limited to a 3DoF experience, it produces a sense of depth when the stereo effect is functioning, however there are no immersive visual cues like parallax, or view dependent reflections and specular highlights. 360° Omnistereo content is challenging to produce as it requires significant knowhow and, to date, there are limited off-the-shelf production systems for creating it. Accordingly, omnistereo content is rare to find, but high-end production teams have released examples of 360° omnistereo for VR systems like Samsung GearVR, Oculus Rift and HTC Vive.
360° volumetric video delivers a VR experience with six degrees of freedom (6DoF) for the deepest levels of immersion. The methods of capturing volumetric video vary and can include a spherical cluster of cameras working in conjunction with Lidar to capture 3D geometry on set and record video of both static and action scenes. Some systems rely solely on a spherical cluster of cameras and use photogrammetric techniques to compute a mesh or point cloud. In both of these cases the imagery and geometry are processed into stereoscopic VR content with depth and parallax. The amount of parallax is determined by the size of the volume that has been processed. These processes do not deliver view dependent lighting as the specular highlights and reflections were captured from relatively small spherical cluster of cameras. Light Field is form of volumetric video which provides 6DoF inside the volume and preserves view dependent lighting attributes.
360° Light Field
For the best immersion in VR, 360° Light Field delivers 6DoF live action video, captured by an array of cameras, and processed into a large viewing volume, with numerous 360° viewpoints throughout that volume. Perfect stereoscopic viewpoints with parallax are delivered to each eye, in every direction, at any angle of rotation, based on the position of the head mounted device (HMD) relative to the volume. Light Field is capable of delivering the full set of immersive visual cues such as parallax and view dependent shading effects including interactive specular highlights and reflections. There are no stitching artifacts, and intra-pupillary distance (IPD) can be modified during playback. 6DoF Light Field VR experiences filmed with Lytro Immerge are available at location-based entertainment venues, such as museums, conferences and special events that use Oculus Rift or HTC Vive. Visit vr.lytro.com for dates and locations of current releases: Hallelujah, Sensations of Sound and One Morning.