Green line on iPhone movies in Quicktime Pro

Hello,

Movies recorded with my iPhone 5S are displayed with a green line/border on the left hand side in Quicktime Pro (most recent version). This happens to more than 90% of the videos recorded and there does not seem to be any logic which videos are affected.

The movies are shot in H.264 with 1080x1920 pixels and transferred to my Windows 8.1 pc. I connect my iPhone to the PC and transfer the movies from the iPhone as internal device to Windows explorer (copy and paste).

When I view the movies on the iPhone, in VLC or in Windows Media Player then there is no green border. So I don't think the problem is hardware related.

Cropping or manipulating the videos does not help either, the green line is still there.

Hopefully someone can help me with this!