Video clips truth or illusion

See through the channels tv or online presentation of some of the events combined with indications of video it is it all real or is it that there is manipulation of some sections, some believe that when watching a video clip of any event asserts that he is real and can not be manipulated as is the case with photos, presence of image is no longer evidence of the validity of any order, because the possibility of manipulation is easy and great, but you can fraud happen to the videos?
See a set of sections at the bottom of one of the people in the art of professional video editing.