D1 @ 7fps OR CIF @ 30fps? Which is Better--is Bigger better?

[Toaster 0]

Well the subject says it all... is BIGGER better?

 

What is the accepted standard for CCTV? D1 at 7fps or CIF at 30fps?

 

Obviously my mind tells me D1 should be better - always better to have a bigger image - even if you get fewer of them. But the fluid playback of 30fps looks good too.

 

What is the accepted standard or most commonly used setting for security video?

[Soundy 1]

You aren't using CCTV to "look good", you're using it to capture events, possibly for use as evidence. As "nice" as 30fps looks, it's rarely necessary (especially when you keep in mind that PAL systems find 25fps sufficient, and movies have been using 24fps since long before television video standards were around).

 

The "accepted standard or most commonly used settings" are, or SHOULD be, whatever strikes a suitable balance between video quality and retention/bandwidth requirements, on a case-by-case basis. Sure, D1@30fps would be nice for every system, but it also chews up a LOT of space, when CIF at 1fps may be plenty for a large percentage of jobs.

 

Alas, too many people just go for the bigger-is-better idea and don't actually take the time to determine what's best suited for a particular situation.

 

So the answer is, you need to figure out which makes the most sense FOR YOUR NEEDS, and balance it with storage and bandwidth limitations.

[Toaster 0]

Ok... I would have to agree with you on this... How do I figure out what is best for my needs?

 

The quick run down of this is, I have a store and we had a robbery before the recording cameras (We had 1 camera that was not being recorded, just so we could watch customers while we were in the back - That was a mistake but...). Immediately after the crime - I installed the 4 recording cameras. (too late of course but...) At the store I have them set for D1 7fps. I'm getting roughly 14 days of recording which I think is plenty?

 

At home, I have no clue yet. I bought the system for the store because of the crime, and when I realized I could have 4 recording cameras at home on the cheap, I decided why not.

[SEANHAWG 1]

I'm a big believer in sacrificing frame rate in order to get better quality.

[clearsignal 0]

I would lean toward the D1. You have a better chance of seeing and identifying the offender and that he pulled out a weapon.

 

With CIF @ 30 he'll just look good doing it. Stick with the D1

[Soundy 1]

^Agreed with Sean, in most cases resolution will trump framerate.

 

Retention is something you need to determine for yourself. Our corporate retail clients all insist on minimum 30 days, because that's usually the minimum time it takes for fraud and employee theft to show up (after the month-end books are done). Naturally, when the cops come looking for clips, it's almost always at the 32-33 day mark. One restaurant client specs a minimum 90 days on all their sites. And one site insists on only a week (in fact, they wanted us to make it so it WOULDN'T keep more than a week).

[Toaster 0]

I would lean toward the D1. You have a better chance of seeing and identifying the offender and that he pulled out a weapon.

 

With CIF @ 30 he'll just look good doing it. Stick with the D1

 

 

Pretty funny

[cglaeser 0]

I'm a big believer in sacrificing frame rate in order to get better quality.

 

+1

 

I caught an auto burglar by matching a very small label on a jacket in a night image. One clear image was more helpful than large numbers of low resolution images.

 

Best,

Christopher

[rory 0]

im using D1 7fps on all cameras at my place and its fine. Although one is low res I could probably lower that to CIF, as really its a waste on a low res camera anyway. IMO unless its a low res camera it should be D1 at least, lower frames or not.

[Sawbones 0]

I'm a big believer in sacrificing frame rate in order to get better quality.

 

 

That's exactly right.

 

If you can't see what you need to see (because your CIF picture sucks), you simply have 30FPS of crap.

 

Fewer images (but BETTER images) beats 30FPS of crap any day.

[Kablooie 0]

I like D1 @ 7fps (or even 5fps). I like to play around with the DVR systems and ran some tests for my own benefit not too long ago. I set many different record qualities and compared them during playback both via Internet, local download and converting to AVI format. I also took still images of the different record qualities and compared them. D1 / 7fps seemed to be the sweet spot for me. I'll certainly sacrifice some disc space and frame rate for better quality images.

 

Here's a true story that just recently happened. A person's cell phone was stolen in a store (fast food type restaurant). I was given the timeframe and saved video of the crime. A few days later the theif came back to the store. The employees recognized him and called the police. When the police arrived they didn't want to arrest the guy unless there was solid proof he stole the phone. The employees showed video to the police and they arrested him. That's the difference good quality video can make. I've been involved in other situations where the video was not good quality and it couldn't be used to positively identify anyone.....and that's when you hear comments like "What good is this system? The video is crap. What did I spend all this money for?" Well, you get to retain 4 months of crappy video though

[thewireguys 3]

I like D1 @ 7fps (or even 5fps). I like to play around with the DVR systems and ran some tests for my own benefit not too long ago. I set many different record qualities and compared them during playback both via Internet, local download and converting to AVI format. I also took still images of the different record qualities and compared them. D1 / 7fps seemed to be the sweet spot for me. I'll certainly sacrifice some disc space and frame rate for better quality images.

 

Here's a true story that just recently happened. A person's cell phone was stolen in a store (fast food type restaurant). I was given the timeframe and saved video of the crime. A few days later the theif came back to the store. The employees recognized him and called the police. When the police arrived they didn't want to arrest the guy unless there was solid proof he stole the phone. The employees showed video to the police and they arrested him. That's the difference good quality video can make. I've been involved in other situations where the video was not good quality and it couldn't be used to positively identify anyone.....and that's when you hear comments like "What good is this system? The video is crap. What did I spend all this money for?" Well, you get to retain 4 months of crappy video though

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[Sawbones 0]

Picture quality matters... there's absolutely no substitute.

 

I did a system change-over this summer for a local neighborhood center, from analog to IP. It went from this:

 

 

 

 

To this:

 

 

 

The former is an old 380TVL Pelco B&W... the latter from an Acti TCM-7411 dome (resized to 800x640 for this pic). It's only 6-8 FPS, but with far better picture quality. In fact, it's been more than good enough to ID perpetrators on two occasions so far. The management folks are VERY happy with it.

 

Picture quality matters.

[rory 0]

^ thats gotta be on of the dirtiest cameras ive seen yet

[Sawbones 0]

^ thats gotta be on of the dirtiest cameras ive seen yet

 

Yeah... it was pretty bad. I don't think it had ever been cleaned.

[rory 0]

^ thats gotta be on of the dirtiest cameras ive seen yet

 

Yeah... it was pretty bad. I don't think it had ever been cleaned.

I dont get some clients .. they are like the camera is blurry and out of focus .. or has all kind of spots over it at night ... like yeah its been raining for 2 months straight what do they expect

[Kablooie 0]

Quick, someone invent a little wiper that can be mounted on a dome to clean it at preset times

[Soundy 1]

[Sawbones 0]

 

Ummm... nice "dome," Soundy

[bigcatbobcat 0]

I get the CIF, 2CIF, D1 and Frame Rate but then there is a setting on some DVR's for "quality"? I did a quick hard drive calc and changed the setting from 6 to 3 on "quality" and it cut the neccessary space in half while the fps and resolution stayed the same? what the what? I guess I'll have to play with it to see but what does it actually relate to? Resolution is pixels and frame rate is number of "pictures" but quality?

[Bean00 0]

It's a little hard to explain...

 

Essentially four things control resolution:

 

• Camera TVL(this is hard to figure though, since most Manufacturers misrepresent this number.)
  
• Recording resolution(i.e. CIF, 2CIF, D1. This is the number of pixels in the image.)
  
• Compression type(algorithm used to compress the raw data)
  
• Bitrate(how much data is used to create the image.)

 

Most manufacturers simply refer to Bitrate as Quality, and give only a couple preset options. My DVRs call it Bitrate and allow you to custom configure per channel. So do a handful of others.

 

All four of these options are very important in determining overall video quality.

[SEANHAWG 1]

Yes I find that Bit Rate is just as important as pixel count, case in point, we had a DVR come in which could record in D1 resolution but the bit rate was set so low that it looked awful on playback, just real blocky looking. We had another DVR that I would have rather used that recorded in CIF but it could be set at a higher bit rate. I dont know why some of these DVR manufacturers do now allow high bit rates, even on the highest setting, it doesnt seem to go past 600 kbps sometimes. It seems like it would be an easy thing to do to up the bitrate some more, even on the cheapo DVR's, but I dont really know much about manufacturing. Now when we are scoping out DVR's, we always ask what the Bit rate settings can be set at.

[Toaster 0]

Does having a higher frame rate at D1 sacrifice quality? In other words, would you get 7 clearer pictures a second at D1 vs 15 fps?

 

The bit rate is set to Constant (CBR) at 2048k - there is a VBR option, but that sounds like it would make the files smaller, but you would loose some quality...?

[Bean00 0]

No not at all. Higher framerate is always nice, just not as important as resolution generally.

 

Two independant concepts.

 

Resolution: Size of the image

Framerate: Number of images taken

 

So if you can get higher framerate at D1, and you want "smoother" video, then by all means crank it up. The issue is that most DVRs can't handle D1 at higher frame rates.

 

And your bitrate is excellent. No need to touch that.

[Toaster 0]

This latest DVR I'm using (which is most likely the one I'm keeping) is a 8CH Q-see but manufactured by TVT. And it give me complete control of the 8CH recording options. At D1 I have 60FPS to use as I want, so I can adjust each channel individually... Right now since I only have 4 cameras, I'm getting 15fps D1 on 4CH and the other 4CH are not recording.

 

The other night someone pulled in front of the store, and checked out the store for about 3-4 minutes, happened around 1am, I got the email alert of motion in the parking lot, I was awake, so I "tuned in" and watched live online - over the internet I only get CIF at 7FPS, so after it was over and they left I downloaded (backed up) those couple of minutes of video over the net, took me about 7 minutes give/take (slow DSL at the store)... anyway, the local video plays AWESOME, smooth and fluid.... Thank god it was innocent, these girls had no bad intentions, they were just scoping out the window, noticed the camera - even waved at it. But in all honesty - I couldn't identify them, or make out a plate number because of the headlight glare. I was able to make out the jeep, the color of the jeep, etc... I'm sure the camera is the weak link...

 

But that's why I asked the question

 

Oh, am I right about CBR vs VBR?