Recording police activity - how effective is it?

I wonder how many quotes like this one we might see in years ahead.

The officer wasn’t wearing his body camera, and his police cruiser’s dashboard camera was not activated because the car’s emergency lights were not on, Belmar said.

And then there are systems like this:

"We've got now five cameras in every regular beat officer's patrol car that captures, like, a 270-degree field of view around the car," ... The system captures up to 40 hours of video, which makes it possible for officers to go back in time. If they drive by something that may be important but don't notice it immediately, the technology allows them to revisit it later.

What do you figure the odds are that the fraction of behavior claimed to be abusive that occurred in the (360-270=90) degrees of the car not covered by cameras goes up after the introduction of those cameras? Police officers are likely to know where exactly the blind spots are.

And then there's what happened in a scenario in Ferguson that would have made a far better case there for pointing to abuse than the far-more-dubious case of Michael Brown:

Indisputable evidence of what transpired in the cell might have been provided by a surveillance camera, but it turned out that the VHS video was recorded at 32 times normal speed. “It was like a blur,” Schottel told The Daily Beast on Wednesday. “You couldn’t see anything.” The blur proved to be from 12 hours after the incident anyway. The cops had saved the wrong footage after Schottel asked them to preserve it.

I overall support increasing the recording of police activity, both by the police themselves as well as by bystanders when something suspicious is going on.

It's important to note though that video is only a tool, subject to the limits of those who use it. As outlined above, recording equipment operated by police is subject to human biases. Of course, the same could be said about how recordings are sometimes used against the police.

An example of that that I've previously noted was NBC's strategic editing of George Zimmerman's 911 recording to make him sound racist. The same could be said about Rodney King where you find the following description of the unedited video seen by the jury in that case:

About the time King was moving toward the officer, an amateur cameraman in an apartment across the street who had been awakened by police sirens began shooting video. He had not witnessed the several minutes in which the officers attempted to take King into custody without using their police batons. The videotape of the beating of King lasts 81 seconds. The cameraman took it to a local television station, which edited it to 68 seconds, eliminating blurry footage that also omitted King’s charge at the officer. What remained is what most of us saw again and again on television: white officers savagely beating a helpless black man for no apparent reason.
Covering the trial for The Washington Post, I was a few feet from the jurors when the unedited tape was played for them. The jaw of the jury forewoman literally dropped open; she had suspected there was more to the video than she had seen on television, and the playing of the unedited tape confirmed her fears.

There seems some evidence, as I've mentioned before, that police recordings lower crime but they're not a panacea (and there's amongst other things a need to replicate such findings).

One of the police reforms that I'd support for US policing is an external entity investigating complaints against the police rather than the the police investigating themselves. I recently mentioned the shooting of Walter Scott, and now it seems that there exists video evidence from a dashcam of him tasering an already subdued individual, an investigation of which might have resulted in Walter Scott still being alive.

There's also the question of how those shot should be treated, another issue which should be addressed:

In several recent videos of police killings, officers fail to provide medical attention to the victims they've wounded. Instead of switching from crime-stoppers to caregivers the moment a suspect is injured and harmless, as any compassionate human being would do, officers often either berate the suspect or stand idly by as the victim dies.

As I've argued before I don't think that one need take sides in this issue. Consider the evidence in a particular scenario rather than assuming that one should always support either the police or a possible victim of abusive policing.