The video shows four men playing pool. When they are approached by several other men, an altercation follows.
Officers Paul Powers, Greg Barnes and Sgt. Jeff Planey were all charged with aggravated battery. They have pleaded not guilty.
The officers also face lawsuits filed by the men who say they were attacked.
The case has resulted in an overhaul of the way incidents involving police officers are investigated and in a new edict from Chicago's new police chief.
"This a great police department. It really is. It works hard, and we have a lot of heroes on it. But it only takes an action of a few, you know, knuckleheads to ruin that reputation, and we're just not gonna tolerate it," Supt. Jody Weis said.
Weis spoke with ABC's Jim Avila for a report about alleged police misconduct scheduled to air Friday night on 20/20.
