In an era replete with fake news stories, you might expect video evidence to provide a clearer picture of the truth.
You'd be wrong, said Google engineer Supasorn Suwajanakorn, who has developed a tool that, fed with the right input, can create a realistic fake video that mimics the way a person talks by observing footage of his mouth and teeth to create the perfect lip-sync.
Like any technology, it has great potential for both good and mischief.
Suwajanakorn is therefore also working with the AI Foundation on a Reality Defender app that will run automatically in web browsers to spot and flag fake pictures or videos.
"I let a computer watch 14 hours of pure Obama video, and synthesized him talking," Suwajanakorn said.
Such technology could be used to create virtual versions of those who have died: grandparents could be asked for advice; actors returned to the screen; great teachers give lessons, or authors read their works aloud.
But he worries, for example, that war could be triggered by a bogus video of a world leader announcing a nuclear strike.So Reality Defender will scan for manipulated pictures or video and allow users to raise an alarm.