I have a very different interpretation of that video. Of course, what happened is horrible. But the video makes it quite clear that the soldiers in that helicopter didn't realize what they were doing. It was a tragic mistake. They believed they had found insurgents, and had a rare opportunity to kill opposing combatants in open combat. These are people who have probably seen their own comrades killed or maimed by insurgents many times. At one point in the video, it is clear they think that one of the reporters is carrying an RPG. I imagine such a weapon could take out a helicopter; certainly I would think an Apache is vulnerable to small-arms fire when flying low, so as far as these soldiers knew, they were in a "kill or be killed" situation.

I don't know what the technical definition of a war-crime is, but in my opinion, at least morally, these soldiers are not guilty of any crime.