ipad 4 can't play 1080p videos

Hi,

I am using an iPad4 running iOS8.3. I recently discovered that iPad4 cannot play (and not even display) my 1080p video taken using iPhone 6 in the photos app. However, when i used a software to downconvert the above video to 720p, iPad can play it. Next I did another experiment, I then tried to convert the 1080p video from .mov format to .mp4 (DivX) format - same resolution. Similarly it could not be played.

This lead to the strange conclusion my iPad4 cannot play 1080videos in the photos app?

Any help/advice is greatly appreciated.