In fact, it can't be named hologram. I have studied a lot most of 3D/Stereo viewing technics, and in the state of the science, it is not possible to project an actual hologram. An hologram is not a slide. There are many reasons for that. Everyone must be conscious that there is no way of making an holographic camera (Digital or optical).
Some so called "holographic cameras" are in fact special experimental systems using a classical camera mounted on a moving support controlled by a computer, allowing to catch holographic images of particles in a very small volume of fluid (around 1 cubical mm).
An actual hologram is a photo made on a special photographic film having both high resolution (very small grain) and a thick emulsion layer.
In the thickness of the film (not on the surface, unlike regular films) are caught interference fringes caused by two enlarged laser beams coming from a unique coherent source that has been split in two.
One of the beams is directly casted on the film plane and the other one is reflected on the object that will be holographed and then casted after reflection on the film.
Each point of the film (row of points in the thickness of the film in fact) contains in the interferences fringes the image of the whole object seen from a different angle.
The whole holographic system is set up on a heavy anti-vibration table in an laboratory insulated from noise and vibration. It is usually underground and not in city. A vibration of the surrounding air or the table of 1/4 of the wavelength of the laser is enough to disturb the system and blur the hologram !
The laser is controlled by remote control and nobody is allowed in the room 10-20 minutes before the start of the hologram capture !
No living creatures can be holographed.
Due to the conditions involved, only static objects measuring less than 20 cm can be "easily" holographed. Bigger objects require powerful lasers.
An hologram catches the geometrical characteristics of an object. The actual colors can't be captured, even with 3 RGB lasers. Due to the required mount precision inferior at wavelength level, it wouldn't be possible to create a device to recompose the 3 images.
Due to the principle involved, the hologram support can't be duplicated at identical. It is possible to make an holographic copy of an hologram (hologram of an hologram), but the target hologram will be always smaller than the original.
As the only support of an hologram is a special photographic film, it is not possible to create an holographic screen. When looking at an hologram, the screen is in fact the film itself. Usual holograms are rarely bigger than 20 cm x 20cm, and you look directly at them while a monochromatic light is projected behind the film plane. The image seen can appear in front of the film surface, or behind. It depends on the optical method used at capture (location of mirrors relatively to the object and film plane).
The image can't be seen outside the area of the film. In fact you see a 3D image on a 2D surface. There are transmission and reflection holograms. According to the capture method used, it is like looking through a window or in a mirror.
An electronic holographic screen would have to be composed of thousands of layers of LCD or similar of around 10 nm of thickness each and a digital record file of an hologram would weight thousands of GB per image !
Same thing for the capture. As the support must have characteristics of a thick holographic film, there is no way of creating an holographic sensor.
Currently, it is technically possible to compute an hologram from a Computer Graphic image, but the resulting file has no possible application.
So, even if it was possible to capture it, an holographic movie couldn't be transported on any existing channel (not even fiber optics). Downloading an holographic movie of 1 hour in HD, could require one year on a 100 MB/s fiber optic internet connection, and storing one film would probably require a hard disk as big as a car !
So, simple stereoscopic images requiring only two images for left and right eyes are much more efficient and economical.
Soon auto stereoscopic screens made of microprisms could allow watching movies without glasses in good quality. There are already few TV sets on this principle , but the current resolution is divided by two (half per eye) compared to a 2D HD image, the distance from the screen is critical and the angle of view is narrow.
Holographic projection will probably stay for ever in the domain of Special Visual Effects in sci-fi movies !
By the way : this topic would have a better place in Off Topic section, I think. 
One more thing about holograms. As it is possible to compute an hologram from a computer generated image, one could imagine in theory using a 3D printer printing layer after layer the equivalent content of the depth (thickness) of a chemical holographic emulsion. The problem is that the 3D printer would have to reach a resolution of 5-10 nanometers per dot in X,Y and Z ! A such precision in mechanical machines will never be reached, as it is very inferior to the simple deformation of any parts of the machine due to gravity, inertia and temperature variations !