CCTV showed one of the thugs grab the victim as Ibrahim jumped on a rubbish bin and unleashed a drop-kick.
As the defenceless man fell to the ground, three others join Ibrahim in repeatedly stamping on his head and body.
The appalling attack continued for ten seconds, before the mob walked away in celebration, leaving the homeless man wreathing in pain.
Ibrahim was jailed on Thursday for four and a half years by Judge Euan Ambrose at Bristol Crown Court.
He had pleaded guilty to the attack, which happened on March 4 last year.
Another man and two youths who appear in the video have been dealt with separately.
Prosecutor James Haskell told the court it was pure luck that the victim was not seriously hurt from the unprovoked attack.