Save Depth map video

I have recently purchased an Orbbec Astra camera.

What would be the correct file format to save the depth map frames, How would I go about saving the videos recorded?

I have been able to load a stream but am not sure what format the frames should be saved in so that i can load them for testing at a later stage and still have all the same information.

I am using OpenNI2, OpenCV3.1.0 and C++.