Hologram projectors are capable of projecting three dimension images in the air. They typically only project in a single color, but more expensive systems are capable of producing true color images. Holo projectors and movies that can be watched on them are both referred to as Holos, so context is key. The most advanced and expensive systems utilize hardlight systems to allow the projections to have solid and lifelike mass. If the holo video in question does not support hardlight encoding, the holograms will all feel rock-solid with no variance in texture.
Not enough information for a detailed history as of yet.