[FFmpeg-user] How to identify a video is 3D

[Jai Kumar]

I am working on a program which transcodes video files.

if file is 3D, then convert to 2D
if file is 2D, then don't do anything

So how would I know the input video is 3D?
and also which type of 3D is it..framepacked or split?

I am unable to find any info about these two things in the metadata of 
the file.

I would appreciate any help.

Thanks.
Jai