Taser says its body cameras are used by more than 3,500 law enforcement agencies, including in 34 major cities across the country, Chicago, Dallas and Los Angeles among them. A spokeswoman for Vievu could not say how many agencies in the United States use its equipment, but the company has recently gained footholds in some sizable cities, with contracts in Miami-Dade County, Fla.; Phoenix and Seattle.

Benjamin B. Tucker, the Police Department’s first deputy commissioner, said officials in New York hope to finalize the contract with Vievu by year’s end and to deploy the first 1,000 cameras next year in 20 precincts.

According to the contract, an LE4 can record up to 12 hours of standard-definition video on a single charge. That, officials said, would allow a camera to capture a police officer’s perspective over a typical shift, which lasts 8 hours and 35 minutes.

The cameras automatically add 30 seconds of buffer video when switched on or off, a feature that Vievu says provides a sense of why an officer is interacting with a civilian. Officers will be able to gain access to videos through either a computer or a custom app on their department smartphones, but will not be able to edit or delete videos, which will be encrypted and logged to prevent tampering and unauthorized access.

One of the biggest challenges for police agencies is where to store the vast quantity of footage generated by the cameras. The city, citing a lack of capacity on its own servers, has opted for an unlimited capacity in Vievu’s cloud-storage platform, which was designed in conjunction with Microsoft to meet stringent federal security requirements. The platform was put into use by the Oakland Police Department in February after a city information technology worker accidentally deleted a quarter of the department’s footage during a software upgrade in 2014.