[quote:e959b12837="edwardxbc"][quote:e959b12837="Thomas"]

You wouldn't by chance happen to work for them?

DISCLAIMER - I am starting with a disclaimer right off the bat because this post really has no point .. lol .. other than to lament on the state of video quality in the security industry I suppose. I know we have come a long way, but with the exception of megapixel (which I will talk about at the end) most everything else is still substandard to television from the 1960's. With that said you can read my ramblings .. or run now.

Getting good (or even great) pictures requires much more than just the capture card. As they say, it will only be as good as the weakest point.

Let's start with the capture card though since you asked. First thing is to get the highest resolution capture, and I assume you are using analog cameras since you want a capture card. I will talk about IP cameras in a moment.

Almost all cards that capture analog video (your standard composite camera) will do so at either CIF, 2CIF or 4CIF which relates to the image size in pixels. 4CIF is the highest resolution typically offered which is 704 pixels wide and 576 pixels tall. This is a pretty good size picture but if you relate it to your computers resolution it's probably a little smaller if you run at say 1024 X 768 which these days is considered lower resolution for a computer monitor.

If you relate 4CIF in terms of megapixel, that equates to 704 X 576 = 405k pixels which is less than half a megapixel.

But if your looking for high-res with an analog camera, then you are looking for 4CIF.

The next part of the chain, and the one that is going to degrade your picture, is compression. You cannot get away without compression because if you followed the math earlier every single image when uncompressed will be around a half megabyte. Meaning that at 30 fps you would be storing 15 megabytes per second of video. I would assume that whatever size drive you have in mind wouldn't last long.

So all pictures need to be compressed. Here is where it gets tricky .. all of the capture cards you have probably looked at don't compress the video. Nope. They pass the entire uncompressed image which was digitized by the card to the DVR software. This means that the whole 400k image is passed over the PCI bus to the processor. It is actually the DVR software that does the compression. (I will touch on HW compression in a moment)

All DVR's use some flavor of one codec (the compression part) or another. MJPEG used to be popular, but now MPEG4 has taken pretty firm hold. The thing to keep in mind is that every codec used in security is a lossy codec meaning that the restored image will never look as good as the original. In order to compress down to the small sizes required it has to dump a ton of quality data. There are other wonderful non-lossy codecs out there, but they are not used in the security industry because of the processing power needed and the fact that it takes longer to compress than capture.

So the question you are really asking is not "what is the best capture card", it is, "what is the best compression codec".

My answer to that is none of them. The two newest codecs in popular use are MPEG4 and H.264. Both are wonderful compared to the codecs we all used earlier, but when compared to the world of codec's they really sort of suck. A big part of the problem is that both codecs are optimized for real time video.

At this point you will have to excuse me because a discussion on codecs that reduce temporal redundancy (such as mpeg and h.264) quickly degrades into techno mumbo jumbo so I am going to simplify and leave a lot out .. but ...

H.264 and MPEG4 are both designed for 30 fps, but most security is recorded at lower frame-rates. What happens is that if you lower the frame rate to say 1fps, you have now completely eliminated these newer codecs ability to effectively reduce file size because they must capture a certain amount of keyframes regardless of the framerate.

Another codec that is somewhat passe at this time is MPEG2. MPEG2 was/is the standard used for broadcast television (i.e. satellite/DVD's) .. so it is broadcast quality. While this used to be good, you may have taken notice that we are now buying HDTV's .. because we have now decided that NTSC broadcast quality also sucks. LOL The real problem with MPEG2 though is that it produced huge video files, so it was rough on storage. MPEG4 and H.264 are roughly as good but with much smaller file sizes.

So, what was the point of all that? Simply that if you really want good pictures/video it really does not have much to do with the capture card. In the end the codec will kill your chances of great video, and even if you pick the best codec, it's really all in the implementation by the DVR software manufacturer because that is where the quality issue is really decided.

There is another flavor of analog camera compression which takes place on the capture card called hardware compression. It's really the same codec but it's done on the card instead of the processor. Companies like HikVision and others offer these for a reasonable price and they typically use H.264. And while the pictures look pretty good, it's still limited to that 4CIF resolution and marginally good codecs such as MPEG4 or H.264.

Finally I want to talk about "REAL" quality video in the security industry and that is megapixel IP cameras.

Right out of the gate we are talking image resolutions of around 1.3 megapixels and heading up to 5 megapixels in routine use in the security industry. These are still compressed with MPEG4 or H.264 but you have so many pixels that the image still looks wonderful. And, it does not even require a capture card because the camera does the compressing.

But of course they are expensive.

So what do I recommend? Look for a hybrid solution that can handle megapixel IP cameras. For cameras where routine quality is ok, use the cheap analog cameras. For the few places where you really need that intense quality, use a megapixel IP camera.

Confused yet?

Hawkeye Advanced MPEG-4 DVRs

And how would you address low light situations in which megapixel cameras fail miserably?

These exist now, just not cheap.

I don't know Thomas. Add more light? Wait for megapixel technology to get better?

That is a good point and a real issue though since the CMOS chips used in IP cameras are far from being as efficiant as the CCD chips in most analog cameras.

With the rich detail of megapixel though, there are applications where they a definite advantage, wouldn't you agree?

What do you think of the new IQeye750 Day/Night Series camera? I have not had a chance to see it in action yet, but I am told that it is sensitive down to .09 lux in night mode and can be used with IR.

Colin, is $1,200+ expensive for a camera? HA HA

In certain situations though, like over cash registers this can sometimes replace several cameras so that helps I think.

But yeah, the cost can put it out of reach .. but those pictures!

[quote:ef12c95d29="CollinR"]

These exist now, just not cheap.

Look at Arecont Vision, if you want an out of the box solution many are now true day/night.

Me personally I have a 3130 (2 imagers both 1/2") and a 3100 that I removed the IR filter from and installed a 1" format machine vision lens. It can see pretty well in .2lux ambient with a 75' rated IR cannon out to about 700'.

IMHO GV gives the best image out there.

[quote:e0255031f6="edwardxbc"][quote:e0255031f6="Thomas"]

You wouldn't by chance happen to work for them?

You make some good points here... I'll add a couple of comments.



Another limitation of analog is the analog video signal itself. Since NTSC video has a maximum of 525 TV lines, and PAL a maximum of 625 lines, that pretty much limits the maximum possible resolution regardless of the capture card. Cheaper cameras with smaller CCDs output even fewer lines - 480, 420 and 380 TVL is common. Some higher-end cameras do 520; some of the really cheap board cameras come in <300. Regardless of what resolution you sample at, your vertical image resolution will still be limited by the capabilities of the camera itself.



There are a few others also in use that work well. The Vigil DVRs use an AZTECH codec, which I believe is based on H.264 but is optimized better for security recording (MPEG4 is also selectable as an option). The newer VideoInsight systems also allow (and include) Windows Media Video (WMV) 9, which in my experience works fairly well. A well-designed system will allow you to select the codec used on a per-camera basis to optimize for different viewing/recording conditions - Vigil and VideoInsight v3.x support this (VI 2.x and older don't).

Some may also allow you to use any installable codecs available - DivX, for example (which is MPEG4-based).



And the major drawback to hardware compression is, you're stuck with it. With software compression, the manufacturers could provide an updated codec with improved performance/quality... with hardware compression, unless the card is flashable (unlikely for cheap cards), you don't have that option.



It should be noted, just for completeness, that there are QIF/CIF/4CIF IP cameras available as well. Some of the same advantages apply, such as on-camera compression, no need for a capture card, and so on, but of course still with the lower resolution. They tend to be sold as webcams and consumer-grade surveillance cams; not something you'd generally want to use is a pro installation, but as I said, I'm just tossing it in there for completeness of information :)



That's what we've been doing for a while now. The Vigil systems support a mix of both analog and IP cams, so we're even retrofitting a few existing installations with IPs. VideoInsight has a separate "IP Server" module that can be installed stand-alone on a PC for an NVR system, or on one of their "Analog Video Server" systems to create a hybrid recorder. Others have their own variations on the theme; again, those are just the ones I'm familiar with.

Excellent addition and very informative. I certainly had forgotten about the limitations of the NTSC format as well! Thanks for your input.

Just a correction (I musta been half-asleep when I wrote that), Vigil's AZTECH codec is based on Motion-JPEG, not H.264. The files created are all .MJP extensions.

I know of a 16 channel full d1 system. Don't know about megapixel support though