What color have you used fot status bar in whatsapp?
Its difficult to ser it correctly, Ive found similar color not The but that uses the app.
because I did't find it and i was really wanted it i made a screenshot and looked it up with gimp:
what rom are you using?
in some builds of shpongle for example, it's a known bug, that there are no video thumbnails..
video playback should be alright.