Simon Gosling is a senior producer at the London-based Moving Picture Company, which creates post-production special effects for the film, music video, and commercial industries. He describes one possible method for how such a videotape could be faked: "First of all, what they would do is take footage of any old conversation between bin Laden and an associate. You would track the movement of bin Laden's head -- of course, he turns his face while he's conversing like anyone would. So the first thing the 3-D [three-dimensional] animator would do is track the movement of bin Laden's face. That would give him what we call tracking data. Then he would make a fake 3-D jaw, which is made easier because he's got a woolly beard, [so] you don't have to match all the skin textures up."
He says the technique is similar to that used in the film "Babe," which features a talking pig: "Then you would animate the mouth and the beard and then you would apply the animation to the tracking data, so that wherever your animated 3-D jaw replacement is going, it follows the live action movement. You light the 3-D beard in the 3-D computer studio and give it the same lighting and direction and intensity of lighting that bin Laden would have had."
Then, Gosling says, animators would add some prepared sound bites and stitch the two elements together. The finished product would look like a single recording. Moreover, he says, the grainy, poor quality of the bin Laden footage would be an asset to any would-be faker.
But industry professionals, he adds, would be able to "see the joins."
"I would have been able to see if that had been done, with my experience, and I would say that having seen the footage several times in the news, that hasn't been done, in my opinion," Gosling says.