The full 30 minute short film by John Hillcoat that was shown on TV. From the description:
Red Dead Redemption: The Man from Blackwater
The director of The Road and The Proposition, John Hillcoat, brings you an entirely digital Western short film. It uses Rockstar's rich open world in Red Dead Redemption to tell the story of John Marston's struggle in the new American Frontier.
I'd rather not see it until I've finished the game. But for those of you that have finished the game, let us know if it's a new story or if it follows or spoils the game story line.
Looking at John Hillcoat's IMDb, he hasn't made a lot of things. He likes to make westerns that's for sure though.