TMZ Sports has obtained video from the violent altercation in Pittsburgh involving Darrelle Revis -- in which you can hear a man bragging about knocking two guys out cold. 

The identity of the man doing the bragging is unclear -- and Revis has denied wrongdoing -- but Revis is the only person charged with a crime in this case ... so it appears officials believe the voice is Darrelle. 

We spoke with a rep for the Pittsburgh Police Dept. who confirms the video is from the Feb. 12th incident involving the NFL star. 

According to the criminal complained filed against Revis, a witness told cops Revis was allegedly screaming, "Do you want to be next?"

In the video, you can hear someone saying, "Shut up before I knock your ass out next."

Revis was arrested on multiple felony criminal charges including robbery, assault and conspiracy. 

For his part, Revis is adamant he was not the aggressor and says he only acted in self-defense from a drunk man who was flexing his "beer muscles."