Yes, there’s an off switch — sort of. No, it’s not likely that anybody’s private moments in the loo — or on the phone with a spouse — will be recorded for posterity. And there’s a battery, but it won’t last forever.

These are just some of answers to commonly asked questions about the new body cameras being worn by police officers in San Diego and other cities in the county.

Here are more details about how police body cameras will work in the city of San Diego. The rules may be different for other cops in the county based on department policies and the brand of camera that they use.

Do cops just press the record button to start taping?

Sort of. The technology makes things a bit complicated.

The cameras used by the San Diego Police Department can be set to a “buffer” mode that continuously records video but only actually preserves the past 30 seconds. Cops can switch the camera to start permanently recording video and capture the most recent 30 seconds.

Let’s say, for example, that a couple of cops are patrolling a neighborhood and suddenly see a shooting take place. If their cameras are recording in the 30-second mode, they can switch them to record continuously and still capture the previous 30 seconds of video.

Taser International, the company that makes the body cameras that SDPD uses, gushes about the buffer on its website and notes that the camera can be in buffer mode for 12 hours or more: “When your honor is on the line, don’t let a 3-second cell phone clip define you.”

Will the cameras record video all the time during a cop’s shift?

Under the San Diego Police Department’s 11-page policy about body cameras, cops only have to record video in certain situations. (This means switching the cameras to the mode where video is recorded permanently.)

These situations include traffic stops, arrests and detentions, among others, although cops aren’t supposed to switch their cameras to record until it is safe to do so. That could create quite a loophole, of course, but the police policy clearly spells out how things are supposed to happen: “Officer Safety takes Precedence over Recording Events.”

Do cops have to alert people that they’re on camera?

No.

“Private citizens do not have a reasonable expectation of privacy when talking with police officers during the scope of an officer’s official duties, even when the contact is in a private residence,” the police department policy says. “Therefore, officers are not required to give notice they are recording.”

But there are a couple exceptions. One’s for regular citizens: “if asked, officers shall advise citizens they are being recorded.” And there’s another exception for anyone who complains about a member of the Police Department or is a witness regarding a complaint: Officers and supervisors involved in investigating this kind of complaint have to let these people know that they’re being recorded.

Can members of the public demand that cops start or stop recording?

They can try, but police officers don’t have to comply.

Will cops record themselves just casually talking with people on the street?

The Police Department frowns on this. “Generally, officers should not record informal or casual encounters with members of the public,” the policy says, because it could hurt relations with the community and prevent people from sharing information.

What about sensitive situations?

The police policy says interviews in child abuse and sex crime cases will not be recorded. Other witness and victim interviews will “generally” not be recorded.

However, the policy says cops should make exceptions for domestic violence victims with serious injuries — and their children — but only if the victims and children are willing to be recorded. This is because “domestic violence victims often recant their statements as early as the following morning after a crime. Victims may also make their children unavailable for investigators or court to avoid their providing statements.”

Are there places where cops aren’t supposed to record video?

Yes. Cops aren’t supposed to record video in locker rooms, dressing rooms and restrooms. Nor are they to be used during medical examinations or psychological interviews, such as during certain situations involving people who may have mental problems. Officers also aren’t supposed to record video in jail.

Can cops record video in my home without my permission?

Yes, if they have a legal reason to be there.

What about at protests?

Cops aren’t supposed to permanently record video at protests, but they’re encouraged to keep their cameras on in the “buffer” mode so they can instantly switch to the permanent-record mode and capture the previous 30 seconds and anything going forward.

SDPD did use the cameras during a recent protest, and there’s a reason for that, as Liam Dillon explained earlier this week (emphasis added):

In general, the department’s body camera policy advises against recording peaceful protests. But the City Heights protests weren’t peaceful. Police officers were hit with rocks and full water bottles and officers were spit on, according to SDPD. Six protestors were arrested.

Zimmerman told KPBS that the body cameras went on when officers deemed the protest an unlawful assembly, which is consistent with department policy.

What happens to video after it’s permanently recorded?

Officers return to their station and place their cameras into docking stations that charge them (the camera batteries are supposed to last 12 hours) and download the video to a protected website called evidence.com. Officers can look at their own video there, and they’re supposed to annotate it with information about the details of incidents like case numbers.

Will supervisors watch the video to see if cops are doing a good job?

Not routinely. The policy says “it is NOT the intent of the Department to review digital evidence for the purpose of general performance review, for routine preparation of performance reports, or to discover policy violations.”

In fact, the body-camera policy lists only a few kinds of cases when police bosses can review video, such as incidents involving the death of a cop or when an officer fires a weapon at a person.

Who gets to approve whether video becomes public?

The police chief or someone assigned by the police chief to this role. So far, it seems that Police Chief Shelley Zimmerman will only release video in extreme circumstances.

When it comes to police misconduct, do body cameras even matter?

As the New York Times pointed out last week, there are plenty of questions about the value of body cameras. They might be off when drama unfolds, or the video they capture may not “lead to universally shared conclusions.” And even if many viewers agree about apparent misconduct caught on video, as in the Eric Garner case, the justice system may not concur.

In a town in New Jersey, body cameras have actually helped cops defend themselves against allegations, according to a police commander who talked to Al Jazeera. He said video cleared cops in five of six cases of alleged wrongdoing: “We’re not fighting cases anymore. There’s not too much to dispute. There’s no more he said/she said. You can see it right there.”

There is indeed evidence that links the use of body cameras to fewer complaints against officers.