The video, taken by cameras on the bus, shows two young men getting on about 9 p.m. at the mall after other riders had taken their seats.
The two men paid part of the fare and began arguing with the 47-year-old driver about the price, Vanore said.
After a lengthy dispute, the driver told them they could sit and pay the rest when they reached their destination.
About an hour later, at 12th and Market Streets, the driver told them to pay less than $3 each as they were leaving, authorities said.
That was when a second - and much more intense - argument flared up. The driver kept the door open so both men could leave, but only one made a move to get off the bus. The other went after the driver, who was cornered behind the steering wheel, and repeatedly punched him in the head.
The video also shows at least two witnesses reacting to the attack. A man walked up to the bus, saw what was going on, and took off. A woman went up to the bus and apparently yelled at the two men during the attack and as they casually got off the bus.
"These two individuals obviously just thought they could pretty much proceed as they wanted, and we would really like to charge them and take them off the street," Vanore said, adding that the driver "was in a position where he really can't defend himself."
The man who punched the driver was described as black with a light complexion, 16 to 19 years old, about 5-foot-5, with a thin build, and clean-shaven. He wore a blue jacket with a white stripe.
His companion, also black but with a dark complexion, appeared to be 17 to 19 years old, about 5-foot-9, husky, and clean-shaven. He wore a tan, three-quarter-length leather jacket.
The two face charges of robbery and assault.
Anyone with information is asked to call Northwest Detectives at 215-686-3353.
Contact staff writer Barbara Boyer at 215-313-3004 or firstname.lastname@example.org.