The officer wounded, John Moynihan, is white. Angelo West, the gunman shot to death by officers, was black.
After the shooting, community leaders in the predominantly African-American neighborhood of Roxbury, where the shooting occurred, were quick to call for calm. One said the officers were forced to return fire.
Still, they were glad to see the video released for the sake of transparency.
"I think people understand that the decisions Mr. West made put his life in grave jeopardy," clergyman Mark V. Scott told CNN affiliate WCVB.
West had several prior gun convictions, police said.
Moynihan is a former U.S. Army Ranger who was honored at the White House for his heroism in the wake of the Boston Marathon bombing. The "Top Cop" helped save a transit officer wounded in a gunbattle with the bombers.
Last month, he became a gunshot victim
when he and other officers in unmarked cars, but with blue lights flashing, stopped the car West was driving.
When Moynihan opened the driver's-side door, the video shows, West sprang out and fired a shot with a pistol at the officer's face. As West ran away, he fired back at the other officers with his .357 Magnum handgun, police said. They returned fire and killed him.
Moynihan, 34, survived with a bullet wound under one eye. He was placed in a medically induced coma at a Boston hospital.
On Saturday, Moynihan was released from the hospital.
"His condition is best described as serious but improving," Boston police said in a statement. "In the days after the shooting, John and his family have been strengthened, humbled and inspired by the outpouring of love and support they've received -- not only from his closest friends and fellow officers -- but also from concerned citizens and strangers from all over the country wishing him a full and speedy recovery."
A woman who was driving by at the time of the shooting suffered a flesh wound in the right arm. She was not identified.
Two passengers in the car were arrested on unrelated charges involving an outstanding warrant and a probation violation.
"None of our officers like to use their firearms," Police Commissioner William Evans said at the time. "It's probably the worst thing we have to do in our profession, but here, clearly unprovoked, one of our officers is shot point-blank in the face."
In April 2013, Moynihan was among officers who helped save transit officer Richard H. Donohue Jr., who was shot during a gunfight involving Tamerlan and Dzhokhar Tsarnaev in the days after the marathon bombings.
In the battle, police fired nearly 300 rounds
within five to 10 minutes.
Moynihan and other Massachusetts officers were cited for their "heroic and relentless" life-saving measures on Donohue, who nearly lost his entire blood volume on the Watertown street.
At a White House ceremony in May, President Barack Obama honored Moynihan and 52 other officers as "America's Top Cops.
After Moynihan was wounded and West killed, police and and local leaders sought to allay community concerns at a time when officer-involved shootings have led to protests throughout the nation.
Scott, of the Black Ministerial Alliance of Greater Boston, said Moynihan was shot "assassination-style." He called for calm in Roxbury.
"This is not about 'Black Lives Matter,' " he said, referring to a protest movement that emerged after the shootings.
"It's about 'All Lives in the Community Matter,' and it's about the police ... responding to a concern from the community."