Cop needing technical help.

[tmartin 0]

As a detective with the local sheriff's office I have been assigned the task of putting together a surveillance tape review system.

We are running into problems reviewing video tapes from victim businesses on standard VCR equipment. Just through researching the net I have found that there are several types of recorder/playback systems. (multiplex,quad,switchers).

 

My question is are there any playback devices that will clearly playback different recording modes in one unit? What is a good basic viewing system. Or do I have to purchase a playback device for each recorded system?

 

I am a newbie so I am open to suggestions or technical advice. If this topic has been discussed already I apologize, just direct me to the correct thread.

[Securitymaster 0]

Hello and welcome to the forum.

 

For VCR TAPES, all you need is a good Time Lapse Recorder VCR, in which you can change the speed of the playback so that you can slow down the frame rate of the video.

 

There are probably other solutions that I'm not aware of, but I'm sure that other members will be able to lead you in the right direction.

[CCTVmofo 0]

Getting a good time lapse recorder is the first part. I would recommend a 1280 hour time lapse VCR. Many manufactuers make them and you can find them through your local cctv dealer / distributor or on-line.

 

The other part is a Multiplexer. I have had much experience with this particular type of problem. Right off the bat I can tell you that my clients have had a 75% success rate with what I am about to tell you.

 

If the tape you are trying to watch comes from a store that has a multiplexer of any kind you will also need a multiplexer to "decode" the tape. Just putting the tape into a VCR will not work unless you properly configure the VCR with a multiplexer. The mux that I have had success with is from Dedicated Micros.

 

The problem is that all multiplexers are a little bit different. Each compny uses their own protocols. This means that a tape made with a Sanyo multiplexer may not neccessarily playback in a VCR hooked up to an Everfocus. The reason why I have recommended Dedicated Micros in the past is because they basically invented the mux. Therefore, most other mux's are desendants of DM. This is not always the case which is why this only works 75% of the time.

 

The most effective way that I have been able to resolve this problem would be to take a recorder in to the actual system that you are trying to play the tape back from. Meaning, if you have a crime at Wal-Mart then you would take a recorder with you to Wal-Mart and make the tape off of their system.

 

Simply take a standard 8 hour VCR with you and plug it in to an output on their equipment. Play back the tape and record on your VCR. This is effective if you are only archiving the event. If you are archiving the entire tape you will definitely need a Time Lapse VCR.

 

The problem with doing it this way is that you are going to lose some quality. You will be taking an image that has already been compressed and compressing it again. If you do go with this method then try to use the VCRs highest quality settings (i.e. higher frame rate). You may also want to look into an 8mm recorder like Sony's old ZBOX2. These have a much better recording resolution than standard VCRs. You can also go with a single channel DVR, but that opens up a whole other can of worms and my fingers hurt. If someone would like to take it from here feel free.

 

I'll be back tomorrow if you need anymore help, you can always PM me and I will be happy to personally help you.

[rory 0]

You would need the muliplexer that the tape is recorded on, as the protocols are different for each one. Basically you need something to demux the tape, as what actually is on that Time Lapse tape is super fast switching video, full images from each camera individually. If played back in a standard VCR you will probably not see anything. If played back on another mux it may just be super fast switching images as it cannot recognise it. Kalatels are common Muxes and been around from day one, especially in the US ... but there are many more, such as the Dedicated Micros mux mentioned above.

 

Best bet would be to find out what systems your local security companies are using and then get back to us on that.

 

Rory

[tmartin 0]

Alright lets see if I'm catching on.

 

To review surveillance tapes that were recorded on quad or switching devices all I would need is a standard Time Lapse VCR.

 

For multiplex tapes I would need a multiplexer, and hope that it has the same code. (Similar to DVD players with +/-R and RW). But with the proper multiplexer (Dedicated Micros) I have a 75% chance of "demuxing" and viewing the video in a noncompressed format.

 

Keep the suggestions coming.

[baywatch 1]

The easiest & most effective way isto use a PVR like the Archos 400.

 

Take this to the multiplexer or DVR site & record the required footage onto the pvr.

 

You can then display it straight off the pvr or display it on a large screen monitor, download it to a computer or record it to tape.

 

You don't even need to find power for the pvr as it has its own battery.

[CCTVmofo 0]

tmartin, you are correct with your assessment. Baywatch has the right idea with the PVR. The only issues that you are going to run into with that option is getting the video off. However, if you go with the right PVR (make sure it has composite video out) this should not be a problem.

[baywatch 1]

The Archos pvr has both video out and computer usb connection, transfering the images is not a problem once you have recorded them on the pvr.

[rory 0]

Actually I would think in the US you would have more chance with a Kalatel Multiplexer .. also Kalatel was a much bigger player in the industry, next to ATV.

[Cooperman 0]

tmartin,

 

The issue of playing back or copying recordings for evidential purposes, is not simply a technical issue relating to compatible equipment.

 

Whilst copying a recording onto a portable device may seem like a straightforward solution, there are potentially serious quality loss issues that need to be considered. Also in some countries, evidence submitted to court has actually been thrown out for various reasons related to the original source material (a very high profile court case in Australia, the Falconio murder trial, has only just ended despite the CCTV recordings being thrown out by the judge).

 

It would be worth researching some of your law enforcement colleague sites, that may have some detailed and useful information relating to recorded evidence in the States (our rules over here in the U.K. are quite different )

 

You could maybe try the LAPD site, SWGIT, and a few others that I can't think of off the top of my head.

 

Only after you have a better idea about the L.E. perspective on handling recorded evidence, should you then consider what equipment you are going to need.

 

As has already been suggested, it certainly wouldn't do any harm at this stage to make enquiries with both local supply companies and 'end users', to find out what the most common record systems are presently being used.

[rory 0]

though down here there is no actual law that uses CCTV video as evidence in the courts, they still try to use it, both the defence and the prosecuters

 

so basically what i normally do is make AVI files and put those on CD, along with the original raw video format, and the software to play it. This is as far as digital only systems go. Another thing one of my clients does is create standard VCR tapes from the monitor out, and also give that to the police and lawyers.

[AVCONSULTING 0]

As stated earlier you will need a time lapse recorder, I suggest the Sanyo since it seems to be the most compatible with various brands. You'll also need a multiplexer and the Pelco seems to be able to decode the most popular brands. You might want to check with someone at Pelco. Below is a link.

 

http://www.pelco.com/products/default.aspx?id=273

[spytown 0]

her TMARTIN.. you may want to look at the Tecton DRAX multiplexer ..it is the only one that can decode other multiplexer tapes..here is the PDF link for it..

http://tecton-cctv.com/pdfs/Drax.pdf

[AVCONSULTING 0]

The Tecton is a good choice. Didn't know it was still available in the US since they had problems with their US distributor some time back. I used to carry those and they had some very unique features.

[Joebo 0]

It's probably a Robot Multiplexer. By far the largest supplier in the US in its day.

 

http://www.americandynamics.net/products/multiplexer_quad_MVP_duplex.aspx

[spytown 0]

No..Tecton is not made by American Dynamics/Robot/Sensormatic. They are a seperate company , and it is the only unit that can decode a MAJORITY of ALL mux's.

[bryan1656 0]

tmartin,

 

I've been exactly in your position many, many times before.

 

Cooperman is spot on in raising "best evidence" issues.

 

You'll need to seize the original tape as evidence. (Best Evidence Rule)

 

If you need any forensic video, the tech will also want the original.

 

However, for playback immediately after a crime in order to try to identify the perp... it is a whole other matter.

 

And then, you've got to find a way to get a workable copy to the prosecutors.

 

Then THEY have to figure out how to get something to work for the defense.

 

 

 

And if the Def doesn't want to plea, theyve got to figure out how to show it to twelve people and two alternates who couldn't get out of jury duty.

 

You might want to touch base with the DA's Office to see what guidance they can give you.

 

All in all you've been steered in the right direction here. A Good time lapse VCR and a decent mux shold get you good to go at least 75% of the time. I'd also recommend a good video printer so you can print captures out to get to the media. You might also keep an eye out for some other stuff to help you take digital stills to transmit by email, etc. to other agencies, the press.

 

Try hitting up the local Wally World. Get someone in loss prevention or their ITF. They are often very good about donating investigative equipment like that. Alot of other retailers are good with this, too since thier LP folks like to stay on the nice-nice with the po-po. Hit up Target or any other big retailers in your area.

 

You might could hit up any local CCTV guys. If you're working homicides on a burglary budget, you might be able to work something out where an area CCTV tech will be willing to be "on call" for you and let you use their gear.

 

If you want some referrals on LE specific video training, or if there is anything else I can do to help -- hit me on me email, private message, or hit my website for my phone number.

 

HTH

[tmartin 0]

Thanks everyone for your incite. It's good to have multiple views on the matter.

 

Has anyone ever used a analog video converter which connects to your computer and converts incoming signal to digital? Once that is done you clean it up with a video program that splits up the multiplex video.

 

Is there a good overall website that CCTV forum recommends to purchase this equipment? A lot of the recommended devices are hard to find on the internet to purchase. Some of the sites are for dealers only.

[Billyk 0]

WOW, great thread, just what I am looking for! I work for the DA's office and need to be able to view these types of evidence more and more. What bryan1656 stated is spot on. We need to see the evidence relatively clearly and are not looking to do anything fancy. If that type of thing is needed it goes to the labs for the experts to deal with so there are no evidentiary type problems. Thanks for all the info, I'm off to see the boss and get an ok to purchase some of the recommended devices. I will be sure to post my results.

Bill

[CollinR 0]

Has anyone ever used a analog video converter which connects to your computer and converts incoming signal to digital? Once that is done you clean it up with a video program that splits up the multiplex video.

 

 

Thats how I would do it, here is a USB capture device that I haven't personally used but I have used quite a few of their PCI internal hardware.

 

Hauppage WinTVUSB

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

 

You'll need a BNC to RCA adapter often, just plug that in where their monitor does and do you best with their system to get unswitched full screen video.

 

Then you'll have an MPEG2 copy that you can burn to DVD without transcoding so it will play in normal DVD players, also the USPS has deals on their "media mail" which covers DVDs. Also you never directly contacted the evidence.

[Billyk 0]

I have a capture board, Turtle Beach's Video Advantage. I cannot get the time lapsed video stuff I have been trying to look at come out smooth and often looks worse. Am I missing something?

[CollinR 0]

I'm not too familiar with turtle beach's stuff specifically but the concepts are pretty general.

 

I assume the CCTV monitor (on their system) also displays it the wrong speed... Your capture card should record exactly what is on their screen. If you hooked this up to a regular VCR in your office you will have to reauthor the video and change it's display speed. You will be borked if you get on in thats multiplexed but that will make a boatload of the analog systems funtional for your needs. Thats also just part of time lapse, everyone is doing the robot.

 

Keep in mind audiophile VCRs aren't good for much more then 320 lines after they have been used for any length of time. IT WILL look crappy when compared to HD video displayed on a PC.

 

Hook it up to a DVD player and capture a few seconds of a decent movie, then watch it on the PC. If it looks okay then you know you are capturing good. If that looks crappy too (it will full screen on a 19" LCD, thats okay) at it's orginal size (720x480 WS or 640x480 FS) then you need to troubleshoot the turtle beach install first.

 

This might help you.

http://www.microsoft.com/windows/windowsmedia/knowledgecenter/howto/PlayFaster_how_to.aspx

I guess WMP can control playback speed if you just want to see it and capture stills, then no reauthoring.

[CollinR 0]

Might try this too.

 

ftp://ftp.voyetra.com/pub/tbs/videoadv/powerdir.pdf

 

Page 66.

[Billyk 0]

Thanks, That is what I was doing...must be total crap source material. I have been doing VHS to DVD with this setup and the quality is quite good. At any rate we are going to purchase a decent Time Lapse VCR and handle the muxed up stuff on a case by case basis. I really don't want to sink a lot of money in this. Any ideas on a software de muxing kind of thing. I know the forensic workstation folks claim to be able to do anyones mux but I have been unable to find just an app for that.

Thanks again!

Bill

[CollinR 0]

I think you are on the right track now, oh and preech the word of pro installed pro parts when you get junk video. Some of those installs aren't worth the power to run them.

Edited March 8, 2006 by Guest