SBS is the simplest possible 3D input format: two views packed into one rectangular frame. It is the universal input for glasses-free 3D displays. The format is small. The stereoscopic pipeline that has to follow it is not.
Vergence and accommodation evolved to agree on one physical distance. Glasses-free 3D displays force them apart. The conflict is bounded by the optics; whether a product stays at that bound depends on the tightness of the stereoscopic pipeline.
A spatial monitor produces depth by combining two image views, an optical direction layer, eye tracking, and real-time pixel remapping. This article walks through each layer and explains why the pipeline implementation matters more than the optical element.