generating 3D effect through screens and deceiving the user to feal that a 2D photo has some kind of depth or third dimension is called stereoscopy, the technique is very old and the photo below shows a very early stereoscope uses 2 photos each one of them have some offset to create the depth illusion for the person who looks through the tool
Stereoscopy is one of the factors that affects level of immersion, it evokes place illusion or the feeling that you are somewhere else by generating the illusion of depth, this illusion is reached by showing a separate image to each eye.
The video below is recorded using a 3D camera, video on the left is similar to one on the right except there is small offset between each one of them.
https://www.youtube.com/watch?v=umUO_r3NMgM
but yet we can’t feel any 3D effect by watching this video using normal monitors, to feel the depth we still need extra hardware that will prevent the left eye from seeing the right part of the video and vice versa.
to separate the videos/Images into 2 Halfs (Left frame and Right frane), we need one of the following tools