I've had a Sprint Samsung Galaxy Note II (SPH-L900) for 2½ years. I've always liked the stock Camera app that it came with, and I've missed having it around since I replaced the stock firmware with CyanogenMod. As it happens, due to technical difficulties it was necessary for me to reinstall the stock firmware recently, and there was my little friend again, "Camera" (v1.5). Is there any way to capture that camera app from the stock firmware and transplant it to CM 12.1 (or any other custom firmware)?
The short answer is no.
The detailed answer is - it will be difficult - very difficult. The camera from the stock samsung firmware relies on the touchwiz framework to work correctly. Any AOSP based rom comes without the touchwiz framework - and that's one of the best reasons to install an AOSP based rom. So what does this mean in the end?
You would need to modify the application - include the shared libraries and may have to port the framework - it won't be worth the effort. If you're not happy with the stock camera application, try one from the play store - they might even make better pictures.