Desperate for help with Time Lapse and MultiPlexed tapes!

[Billyk 0]

Hi,

New to the forum and to CCTV Analog and Digital. I need to come up to speed pretty quickly and truly appreciate any and all assistance. I am the Network admin, and AV goto person for a large District Attorney's office, over 150 ADAs on board! What I get is requests to help with video evidence provided by the local Police and the establishments involved in crimes. A lot of the stuff is from time lapse and / or multiplexed tapes. What I need to do is get something to help me get a clear version of what I am sent. Can anyone get me started, give me some idea of what questions I should be asking, anything!?!?

Thanks again in advance for anything you can do to help me.

Cheers,

Bill

[CollinR 0]

I would outsource it if I were you.

 

 

Well that is if you ever wanted to use it for evidence, if you just want to look take a PVR and hook it up to any old system's monitor output and manually record what it spits out I don't deal with junk, so I don't kow much about the older stuff.

 

I guess what it comes down to is how crappy of equipment you have to deal with, if it is recording a quad view or only capable of displaying a quad view it's gunna suck no matter what. If it's a quality cam behind a quality switcher you'll have as high quality of a recording as most of the PC based DVRs but you will loose tons of frames due to the switching.

 

Might be able to get by with a laptop and a Hauppage WinTVUSB

http://www.hauppage.com/pages/products/data_pvrusb2.html

 

 

Thier other stuff (PCI PVR models) dominates the best CCTV hardware I have seen.

 

 

If you do it that way you never touched the evidence, there is still no way it could have been manipulated.

[Billyk 0]

Thanks for the quick response.

I am the outsource!

What I should have stated clearly is what get is a copy. I do not get the originals of anything, that is evidence that's been sealed, logged, what have you.

An example would be I receive a tape from an old convenience store, I play it on a regular VCR and the motion is fast and jerky. Is there anyway to get a clearer picture? Another might be from a multiplexed tape and you can barley see anything but you get a sense of different views, kinda. I know my description sucks.

As long as there is a master and I can testify to the lineage of what I give out they can get it admitted into the court as evidence. I do this with audio all the time.

Thanks again

[Thomas 0]

http://www.cctvforum.com/viewtopic.php?t=3829&highlight=law+enfor

 

This thread has some answers to your questions.

[CollinR 0]

Another issue is your quality of service for the justice system. How good are you with video editing and manipulating? Often details are in the video a good technician will be able to find using somewhat specialized tools and knowledge. Even if it's not the evidence copy it can still skew you.

 

I would at least call a few places and see what they want to have a tech extract a copy and enhance it as best they can. That way your ADAs will have a good idea of what can come from the evidence copy if it goes to court.

[Billyk 0]

Thomas, thanks I will be sure to immerse myself.

CollinR, that's a whole other subject, I did a fair amount of research on my own (that's how I found this forum) and through the state. There is a whole branch of this stuff, forensic video. We have a lab in the state that would deal with that. Things like getting a better facial image, license plate, etc. I am not looking for anything as deep as that. The equipment for that sort of thing is readily available if you can afford it and would take a department to deal with it. I am just looking for a reasonable investment to assist the ADAs to view the evidence as we receive it. I also make copies for the defense attorneys as well.

Thanks again! I really appreciate it.

Bill

[CollinR 0]

No problem, I really wish I could say that all timelapses recorded at the same speed and all multiplexors use the same protocols but I can't. It would make both of our lives easier if I could though.

[AVCONSULTING 0]

There was a very complete thread on this regarding the various multiplexer formats and which brand is the best one to use in decoding. You would probably have to search for it, maybe Rory remembers the thread since he has a good read on what is going on here.

 

To boil it down you are going to need a multiplexer and time lapse recorder.

[CollinR 0]

Not totally true, although thats going to work often.

 

 

Any good video capture card should be able to do this. It's a software issue, if it is an MPEG stream it will probably get a keyframe at each camera change. The problem is software developers, if this had the demand that automagically removing commercials from captured TV does it would be a done deal.

 

This is almost exactly what all the cheaper less then realtime DVRs are doing, most of the chips run at 30fps. They are recording in multiplex through one chip and pulling it back apart on the other side. It has a dwell time of 1/30th second so you don't loose as much data. Realtime doesn't get multiplexed unless the chip runs more then 60 fps for 2 cameras.

[rory 0]

There are some demuliplexers out there that work with certain muxes, namely the big brands. I havent looked at software ways in any detail but that is possible also.

 

http://www.clearview-cctv.co.uk/products/clearview/forensic_demux.php

 

also, i take it you've seen this software?

http://www.cognitech.com/

[kk9901 0]

Depending upon your location. You may find that one or aanother brand of muxer is particularily popular (in my area mostly robot at the higher end and atv at the lower). BIG caveat if you are working with copies, these may or may not contain the same muxer info as the original. If not copied correctly this data (inserted in the videi blanking interval) may not survive the copy process. I do this type of work for a major prosecutor so if you need any info you can contact off forum.

 

good luck,

Jerry

gkling9901@att.net