White balance is more important for videography than it is in stills photography, and for two reasons:
There's no RAW file to fall back on: you can't change your mind about the white balance setting later without degrading the image quality.
Continuity: You can't have the camera changing its mind about the auto white balance setting half way through a scene, and you also need to ensure continuity of colour rendition from one scene to the next.
There is some scope for editing the video footage later (or 'grading', in video-speak), but it's not ideal. Instead, you need to think about white balance when you shoot. Auto white balance is too much of a lottery – you should choose a white balance preset instead, make sure it's right for the conditions and then stick to it.
