That’s exactly how it works. The video is placed in a buffer which holds several seconds, and as new video is added the old is pushed out, unless the system detects motion, at which point that buffer is then written to the hard disk along with the motion video.

And Cliff, as I have been working in the security industry for 20 years and writing manuals for digital video recording systems, I’d say that qualifies me as an expert.

http://www.youtube.com/watch?v=ZFzH5Oe-YL4&feature=player_embedded

If you look at the video in question, posted upthread, that excuse (not saying you are making the excuse) melts away rapidly. There’s LOTS of motion going on everywhere and the camera stays on for many, many minutes, with the sole exception being that six seconds when he gets shot.

They’ll also often have automatic media rotation, retention policies (delete after 30 days, etc.).

So it wouldn’t be at all surprising to have a video clip showing motion that begins before the motion.

It is also possible that this particular camera had a zone defined around the door or some other area of interest that was not being triggered by the action with the police at all. It is a remarkable coincidence that the one particular moment in time which would show that the officer is somehow not guilty of manslaughter for shooting and killing a man armed with a bag with beer in it is somehow the moment that is missing. Lucky for him the presumption of innocence thing is really amped up when the defendant works for the government.

A “buffer” is a temporary storage location for data, so yes it is possible to record what happens several seconds before or after motion activates the recording, while saving disk storage space since the buffer is constantly being overwritten/updated. Or I’m just guessing that’s how it works.
Anyway, it’s no surprise that there is no video of Turner swinging the beer cans — amazing how a motion-activated camera stops recording with all that action going on! However, I read an article where his son says that there is another recording out there that shows everything — if so we’ll see how they can find a way to keep that from coming out.

So…cameras can predict the future and start recording a few seconds BEFORE motion starts them? Yeah, you're a 'security expert' alright.

http://freenorthcarolina.blogspot.com/2011/07/most-excellent-post-concerning-guerena.html

I hope Radley put’s MacLeod’s article in The Agitator!

Quotas implemented for Pittsburgh police in Zone 2 which includes the historic and majority black Hill District.

Also, video cuts out at crucial moment in police killing of former NFL’er David Turner; internal investigation clears officer of wrongdoing.

I’m sure your shocked at these recent developments.

Just to let you know, the H&R peeps, and our nuts, are glad you’re out in the world fighting the good fight.

A shame the grand jury doesn’t grow some balls and issue an indictment against the cops. They used to have the power to do that without the direction of the DA.

See, what you guys are failing to realize is that department policy says it’s totally cool to shoot unarmed folks. Or, at least it NOW says that. You can make anything fit a policy when you are the one making the policies.

Being a security systems expert, I can say that it’s quite common to use motion sensing in digital video recorders for security systems. It helps reduce the amount of hard disk space needed to record, as it only records when something is moving.

However, the vast majority of these systems have a buffer which records a few seconds before motion starts, and also continue to record for several seconds or more after motion stops, to avoid situations just as the one described. So I’d say they are lying their asses off.

That’s class, Sheriff Younglblood. True class….

Ademo & I will join Ian & Mark on http://freetalklive.com tonight 7-10pm EST

Background: http://copblock.org/greenfield