BOSTON — Prisoners would have greater opportunities for early release, even if they received a mandatory minimum sentence, under legislation resulting from the cooperation between all three branches of government on criminal justice reform.

The broad outlines of the criminal justice reform bill that Gov. Charlie Baker plans to file were announced at an early morning press conference on Tuesday attended by House Speaker Robert DeLeo, Senate President Stan Rosenberg, Supreme Judicial Court Chief Justice Ralph Gants and other prominent government officials.

“One of the things the bill does is allow people who have been incarcerated for mandatory minimums to earn good time,” Sen. William Brownsberg, the co-chairman of the Judiciary Committee, told reporters Tuesday.

He said the new opportunity to reduce imprisonment through program participation would not be available for mandatory minimums related to opiates or crimes committed in conjunction with violence, illegal gun possession or involvement of a minor.

The governor said more than half of people who are released from houses of correction and state prisons “wind up back in the court system at some point after their release,” and he said reducing that recidivism rate was the focus of the effort.

“Prison is, as it should be, a punishment, but the people of Massachusetts are better served when more individuals exit the system as law-abiding and productive members of society,” Baker said.

The governor suggested he sees value in current statutes that require a minimum period of incarceration for those convicted of certain crimes. He said the bill would “set certain parameters for earning good time for certain drug distribution crimes while still honoring the mandatory minimum sentences established by the Legislature.”

The chief justice of the state’s highest court, on the other hand, sees fundamental problems with mandatory minimum sentences for drug crimes. In his 2014 State of the Judiciary address, Gants said those strict sentencing parameters have a “disparate impact upon racial and ethnic minorities,” and eliminating those sentencing floors would “free up a considerable amount of money” from the cost of imprisonment for use on programming and increases in the salaries of prosecutors and public defenders.

“Why would we require judges to impose sentences that are not informed by the social science evidence regarding what sentences reduce the risk of recidivism and what sentences may increase that risk?” Gants asked in his 2014 address, according to a copy of the speech. “But sadly, in drug cases where the law provides a mandatory minimum sentence, that is precisely the sentencing system we now have.”

While not explicitly calling for the repeal of all mandatory minimum sentences, Gants on Tuesday spoke to “the importance of individualized sentencing.”

Criminal justice reform advocates have been hungering for a major bill since former Gov. Deval Patrick signed a sentencing reform law in 2012, and those seeking a further rollback of mandatory minimum sentences will likely track the bill through the committees and floor debates, where it may be amended.