VR Rendering Question

jay22111

Figured this might be a good place to ask not specifically related to slr but more about vr in general. If you have a standard video that is say 1920 x 1080 for sake of argument. Can you not convert that to 'vr' by showing the left eye a center point of 955 x 540 , then the right eye a center point of 965 x 540 using the same video stream? Thought about this while reading up on vr for gaming, and how it loads a gpu so hard due to the fact its rending two different images. Isnt VR effectively the same video just with a shifted perspective?

I do not really know much about cameras, and clearly not much about VR. So if this question is dumb would love an ELI5 . Thanks !

ibins

jay22111
You could but it would be pretty pointless.
You do not get any 3D effect from this, as there is not parallax difference in showing the same image twice.

The only thing you could do (and is actually possible with most VR video players) is creating basically a big virtual screen in VR and play the video on it. But this would not really be much different to watch the video on a real display.

spacepirate

2d video isn't stereoscopic (3d) and it doesnt have a 180+ degree field of view. you can't fix either of those after the video has been recorded. the only way is to record with a VR camera that has 2 fisheye lenses. a fisheye camera lens gives you the 180+ degree field of view and having two lenses gives you the 3d effect.

jay22111

Ah I c. So there is a perspective difference that comes into play.

ibins

jay22111
Yes left an right eye, or left and right lens have slightly perspective, which is responsible for thee depth effect.

Also usually regular videos are shot with focal lengths with much narrower FOV then needed for VR.

Also in VR you virtually watch the video in a very large size, so only 1080p would be a very blurry image, as can be seen on early VR Videos, and even 4k is kinda low for VR.

mgbgt35

Some video editing software can 'convert' 2D into 3D videos.I tried it with some success.The videos do look sort of 3D,but just 'not quite normal'.They definitely look different from proper 3D videos shot with 3D cam.