(TNS) -- What was once a powerful novelty — a controversial police encounter being caught on video — has become so common that the public now expects that such videos will be captured in all cases and publicly released, bringing light into darkness.

But as expectations of cameras rise, their limitations also come into sharp focus.

Around the Bay Area, more departments are having their officers record interactions, in part to protect themselves from false accusations of wrongdoing. But the technology varies, as does the quality of the footage, how it is gathered, how long it is stored and how it is released.

Moreover, police control the footage. Though leaders at some Bay Area agencies said they are developing strict policies to prevent any altering of videos, there’s an inherent distrust.

That much was clear in the case of Sandra Bland, a 28-year-old black woman arrested this month during a minor traffic stop in Waller County, Texas, before she was found hanged three days later in her jail cell. Authorities said she committed suicide — a finding rejected by her family.

Officials promised a dashboard-camera video from the traffic stop, and when they released the footage on YouTube it showed that the officer had escalated the encounter, ordering Bland out of her car after she declined to put out a cigarette.

But glitches in the video, with images at times repeating while the audio goes on uninterrupted, prompted a volley of accusations — denied by police — that the footage had been edited.

Civil rights advocates said that the rapid rise in the use of cameras, particularly body cameras that officers wear on a lapel or visor, begs for more scrutiny, regulation and policy.

“Body cameras won’t promote community trust if the community can’t trust the video,” said Micaela Davis, a staff attorney with the American Civil Liberties Union of Northern California.

She said police departments that use body cameras should take away discretion from officers, requiring them to turn the devices on every time they encounter a civilian, with only limited exceptions. Further, she said, all videos should be uploaded to a secure server that restricts officers from deleting or editing footage.

Former San Francisco Police Chief Tony Ribera, who teaches law enforcement leadership at the University of San Francisco, said departments also need objective policies for when they release videos to the public.

“It wouldn’t be a good thing for the Police Department to pick and choose what they release — ‘We release the good video, but we don’t release the bad video,’” Ribera said. “Obviously there’s a problem with that.”

Concerns over loose or faulty policies have made their way to Sacramento. A bill introduced by state Sen. Bob Huff, R-Diamond Bar (Los Angeles County), would require each police department using body cameras to create detailed policies in coordination with rank-and-file officers.

Around the Bay Area, though, practices vary.

In Oakland, officers have been disciplined for failing to turn on their cameras, while other cities allow more discretion. In Brentwood, officers are encouraged to turn them on in most situations, with the understanding that “there are times when it wouldn’t be appropriate or times when they are unable to activate it,” said Lt. Doug Silva.

Technology varies as well. For instance, BART said its wearable cameras, made by Taser, have a function similar to a home DVR. When an officer presses a button to start recording, the prior 30 seconds are captured as well because the camera is always on.

But most Bay Area police forces that use body cameras buy them from Vievu, which offers models that are less expensive and do not have the feature.

More questions

The Sandra Bland case also made clear that cameras can’t catch everything — and that sometimes the footage can open up even more questions.

Though the dashboard camera was rolling during the traffic stop in Texas, police critics and others wondered why the officer led Bland off-camera for the actual arrest — during which Bland can be heard saying, “You’re about to break my wrist” and “You just slammed my head into the ground.”

It’s not clear how many Bay Area police agencies use dashboard cameras — no one keeps track — but they have clear drawbacks, said Andrea Roth, a professor at UC Berkeley School of Law and a former public defender.

“We never got to see up close the encounter between the officer and Sandra Bland in the car,” she said. She added that officers know where the camera’s lens is fixed and can often “essentially choose what to put on the camera and what not to put on the camera.”

The limited, front-facing view of dashboard cameras is one reason the Menlo Park Police Department opted for body cameras, said Cmdr. Dave Bertini.

Department officials said use-of-force incidents by city officers have dropped by one-third since they began using the cameras in 2012 — a trend seen in other Bay Area departments.

“We saw it coming down the road and tried to get in front of it,” Bertini said. “It’s become an industry-standard question — why didn’t you have a camera and why didn’t you have it on?”

But even body-camera footage can provide a view that is open to dispute.

The first Bay Area shooting captured on one happened in Oakland in September 2011. The officer, who had shot an armed man who fled from a traffic stop, was initially recommended for firing before he was cleared. The video has never been publicly released.

Palo Alto is trying out body cameras. But for the past year and a half, the police force has relied on a unique surveillance system — five cameras placed on all police cars capture a nearly 270-degree view. There’s a camera in the front, two facing out from the roof, a fourth in the rear and one capturing footage in the backseat. And the cameras are always running.

‘A digital partner’

“It is essentially a silent partner — a digital partner for them — somebody that’s always there that gives us a chance to go back and see what happened,” said Lt. Zach Perron. “The cops love it.”

Perron said only two employees — both civilians — can delete footage, and only in certain situations under state law and city policy. Editing is not possible, he said, with videos of traffic stops and other interactions automatically uploaded.

Similarly, in Menlo Park, footage cannot be edited, Bertini said. Only one employee can delete videos, he said, and only in limited circumstances and after the police chief has signed off.

John Burris, an Oakland attorney who represents victims of alleged police brutality, said the less discretion an officer has over a camera and its footage, the better.

“The concern you obviously have with those is the fact that the officer himself controls it,” Burris said. If officers don’t turn on a body camera on time, he said, you “may not always have the very beginning of how the event takes place, and it’s subject to interpretation.”

To Roth, the UC Berkeley law professor, the Sandra Bland case suggests that police have little choice but to aggressively deploy cameras.

“The fact that so many people now know that (police) abuse occurs routinely,” she said, “means that the absence of cameras would threaten the legitimacy of police authority even further.”

©2015 the San Francisco Chronicle Distributed by Tribune Content Agency, LLC.