iPhone 4S Camera. I see "black bars" on side of videos I take when I post to FB or YT

[diegobrucie]

I have an 4S. I shoot videos which look good and appear "full screen" on my phone. But when I email, post to Youtube or Facebook there are black bars on the side, rather than appearing as a full screen video. Why is this happening?

 

[simba4]

Show some pics!

 

[diegobrucie]

 

[Jmpx55x]

Take the video with your iPhone sideways instead of up and down