GILROY, Calif. — About 3,000 miles from New York, members of a camera crew gathered around Anthony Quijada, trying to do for their not-famous, not-rich client what some high-priced lawyers are doing for theirs in New York courts: Make a video that can keep him out of prison.

Lawyers are beginning to submit biographical videos when their clients are sentenced, and proponents say they could transform the process. Defendants and their lawyers already are able to address the court before a sentence is imposed, but the videos are adding a new dimension to the punishment phase of a prosecution.

Judges “never knew the totality of the defendant” before seeing these videos, said Raj Jayadev, one of the people making the video of Mr. Quijada, who lives in this Northern California city of about 52,000 people. “All they knew was the case file.”

Yet as videos gain ground, there is concern that a divide between rich and poor defendants will widen — that camera crews and film editors will become part of the best defense money can buy, unavailable to most people facing charges.