MOSCOW — Struggling to calm bubbling discontent, the Russian authorities on Friday freed a jailed actor whose conviction just days earlier for a supposed attack on a police officer had prompted pickets in front of the Kremlin’s executive office and a rare public show of solidarity from fellow entertainers, priests and teachers.

The actor, Pavel Ustinov, 24, was released from custody pending an appeal that will be heard next week. On Monday, a trial court in Moscow sentenced him to three and a half years in a penal colony for assaulting a police officer during his arrest at a recent protest rally in central Moscow.

The trial judge refused to admit as evidence a video that appeared to contradict the prosecution’s case, relying instead on the testimony of the officer, whose shoulder had been dislocated during the arrest. Prosecutors called for a sentence of six years.

The video showed four officers in riot gear attacking Mr. Ustinov in a busy Moscow square at the time of a protest rally nearby, pushing him to the pavement and hitting him with rubber batons. It was not clear why they had singled him out.