Even though the Cinera has been primarily marketed to movie fans, many photographers specialized in 3D photography have recognized the potential of the Cinera as a stereo stills viewer. Many of those 3D photographers use cameras that output an MPO file (containing a left and a right image) and many others using other equipment save their stereo images as MPO files.
I have been asked several times by 3D photographers if there is any way to view MPO files with the Cinera. The answer is a definite "yes" ! 3D photographer Andy Modla created an app called "3D Stereo Photo Viewer", which was designed to display MPO files as side-by-side images on phone displays. With phones, the app functions are activated by touch. But they can also be activated using a Bluetooth controller.
I decided to test if Andy's app would work with the Cinera's built-in buttons and this is what I found:
One can navigate to the app and open it using the left buttons, where it will display a few sample images that can be scrolled through using the top or bottom buttons (on the left). To access one's own folders however, a regular mouse must be used to pull down the menu bar at the top, click the three lines and then click "browse". Again with the mouse, one can navigate to the folder of one's choice and open the first image.
From then on, the top and bottom buttons at the left may be used to advance from one picture to the next. The top button will advance pictures forward, while the bottom button will move them backwards. Pressing the OK button starts the slideshow. Double-clicking the OK button stops the slide show.
In other words, a simple mouse is required to navigate to a given folder. However, once it has been opened, the left buttons (top, bottom and center) on the Cinera are sufficient to navigate through the folder or play a slideshow. (Note that the left and right buttons only show the first two pictures in a folder, Therefore they are useless with this app.)
Navigation is also possible using a common inexpensive Bluetooth game controller as outlined here:
The 3D Stereo Photo Viewer app is free on Google Play.