Need help making Digital VCR

wizardPC · 01-03-2002, 03:10 AM

I have been appointed chief of security at the ole frat house, and I want to get a 4 camera surveillance system with a digital 4-way multiplexor (aka a quad--makes all 4 cameras show up on the same screen).

I can get all that for about $450, but those nice 24-hour looping VCR's are darn expensive (cheap ones are $500).

We currently have an old P75 machine (running linux, but I can change that if necessary) acting as a file server sitting in a utility closet, and I was wondering how I could go about getting a 48-hour loop of video. I know I need a video capture card and a huge hard drive, but what kind of software do I need to get? and where can I get it? will that p75 even be able to do this?

This needs to be an autonomous recording system. the only time we would be looking at it is when something happens to the house (like our front window that got busted out the week before christmas).

any help is greatly appreciated. If I ask the people I am getting the cameras from they'll try to sell me a digital video recorder for like $2500.

MikeHunt79 · 01-03-2002, 08:12 AM

It is possible, but u would need a HUGE drive, probably about 100gb.

For example, i capture a simpsons ep. (20 mins long), then the file size of the captured video is about 2.5gigs. This is a broadcast quality (720 x 576) with cd quality sound. I also use MJPEG compression on capture, otherwise the data couldnt be written to the harddisk fast enough; so get a capture card with realtime MJPEG or MPEG compression.

If you lowered the capturing resolution, you could reduce the filesize. You could probably get about an hour of video into 1gb at half resolution (360 x 288), but the captured video would have less detail.

You also need to use a program called VirtualDub in order to overcome the 2gb file size limit, but it not too much trouble to use.

Im pretty sure a p75 should be ok, but it might not be able to capture at full resolution. I used a p200 for video capture for a while, and it seemed ok.

wizardPC · 01-03-2002, 02:03 PM

as far as quality goes, these cameras and the quad are NTSC, so anything higher than 600x420 would be overkill--and there is no audio on these cameras.

So lets say I get a 60GB hard drive and a video card with realtime MJPEG compression. Would I need to (and be able to) alternate capture files (ie, yesterday.mpg, today.mpg) so I can overwrite old data? or could I just have one huge file that would act like a looping video tape so the beginning of the file is exactly 48hrs old?

Could that VirtualDub do that? or does anyone know where I could get a program that would?

ODYSSEY · 01-03-2002, 04:31 PM

You could always capture at a low frame per second. TV is 29fps. IMHO that would be overkill for what you are doing. 5-10fps should be fine for capture. TV is also 352x240, which is also MPEG1. MPEG2 is 720 x 576. An ATI Wonder VE or I/O magic PVR, would be the best bet, both capture MPEG1/2.

PaulzY · 01-04-2002, 08:34 AM

get a set of x10 cameras, they got some software to have them up, 4 displayed on a screen at a time and it goes straight to comp, u can zoom in etc.

an alternative idea, have u allready got the cameras ?

oh yeah another point, u can convert mpeg2 to divx in realtime now, so u might be able to set that up, u will need a p4 2gig or an amd xp 2000 or something

wizardPC · 01-04-2002, 11:30 AM

Do you have a direct link to those cameras?

I have not bought the cameras yet--I will be making the proposal to our alumni association in february, at which point I may get a budget. But, I need to at least have a ballpark figure--and it needs to be a low figure, less than $700 or so, otherwise they'll be very hesitant. So that means a new computer will be out of the question.

HarryBits · 01-04-2002, 05:12 PM

What about a Tivo? Buy the smallest version possible, then upgrade it yourself. Still, this option is about $400 with the new harddrive, but it'd do what you want and it's cheaper than a PC. You can build/buy a network card for it and transfer the video to other PCs to burn to a CD or whatever.