I've noticed that I get faint dark lines during video playback from all sources, whether it's qqplayer, the built-in video player, youtube etc. and the source doesn't seem to matter. This happens in all the video formats I've tried, mp4, avi and others. They appear as faint dark horizontal lines (when the phone is in portrait mode) and vice versa. I've searched all the forums and can't seem to find an answer. Is my phone defective or is this a limitation of the GPU? Note that that the lines do not appear when viewing a static picture.