This is actually pretty dope. B is quite the entertainer and there is no arguing it. This was filmed at her rehearsal for American Idol. According to Hov himself via his fancy website:
Sometimes you need perspective. You’ve been right in front of greatness so often that you need to step back and see it again for the first time. This is the dressing room rehearsal for American Idol. NO MICROPHONE. No effects.
Check out the official version the song as well.