ZoneMinder Forums

Hi Guys,

My first posting and and as is usual for a first posting its when somebody wants help/info

I recently bought a 480TVL CCD camera from Ebay but my tests seem to prove otherwise.

Running it at above 384x288 ie 640x480 for instance gives me interlacing problems. Running at 384x288 gives me fine results but I paid for more and I want more.

The point is, I suppose, that this camera is to replace my camcorder which I have been running at 384x288, 640x480 and 720x576 and not once have I seen an interlace problem.

Now the other cameras I have are 300TVL which I run in 384x288 with good results. Running these at 640x480 give me the interlacing problem. So it seems to me that the new 480TVL camera is anything but and is no better than 300TVL.

So my question is, has any one bought a cheap 480 or 420TVL camera off Ebay and got the results they expected? Are the reputable suppliers in the UK which seem to be selling the same stuff meeting the specs they say they are?

I spent £30 on this cheap camera, I would have hated spending the UK price from a local supplier for the same results.

Thanks
John

More on 'Was I scammed?" in a minute.

The interlacing problems you are talking about is generating from the capture card and no so much from the camera. A limitation of the BT878 chipsets is the higher resolution you throw at the capture card (ie 640x480) the more "interlacing" you will receive. There isn't much you can do about this besides spending even more money and getting a network video server and pulling 640x480 from that.

As far as "Was I scammed?". Who knows. There is no governing body that controls what a company claims their camera can do (TVL wise). Alot of the cheap chinese knockoffs might be 380 / 420 TVL marked off as "480TVL". It's typically better to buy a camera from a company that at least puts their name on it and has shown to have good, reliable products.

As far as UK supplies James Wilson has a website and is a member of this forum. He should be able to help you...i think his website is:

http://www.securitywarehouse.co.uk

sledgehammer wrote:Hi Guys,

My first posting and and as is usual for a first posting its when somebody wants help/info

I recently bought a 480TVL CCD camera from Ebay but my tests seem to prove otherwise.

Running it at above 384x288 ie 640x480 for instance gives me interlacing problems. Running at 384x288 gives me fine results but I paid for more and I want more.

The point is, I suppose, that this camera is to replace my camcorder which I have been running at 384x288, 640x480 and 720x576 and not once have I seen an interlace problem.

Now the other cameras I have are 300TVL which I run in 384x288 with good results. Running these at 640x480 give me the interlacing problem. So it seems to me that the new 480TVL camera is anything but and is no better than 300TVL.

So my question is, has any one bought a cheap 480 or 420TVL camera off Ebay and got the results they expected? Are the reputable suppliers in the UK which seem to be selling the same stuff meeting the specs they say they are?

I spent £30 on this cheap camera, I would have hated spending the UK price from a local supplier for the same results.

Thanks
John

As curtis says he is right regarding the interlace fact. But please dont think that the stuff on ebay is the same as all shops sell, some of it is but i have seen some of the stuff that comes from ebay and seen samples of stuff from china. The poor stuff that we wont import is what ends up on ebay.....

Worse still, the stuff that didn't pass our QC tests from China got sold in bulk on eBay. If you can not afford to test a half dozen, only buy cameras from a reputable shop that takes returns.

Sorry...I didn't mean to say *all* ebay camera stuff was junk. Some of the cameras on ebay are good quality cameras. But ebay has been flooded with cheap crappy stuff.

jameswilson wrote:As curtis says he is right regarding the interlace fact. But please dont think that the stuff on ebay is the same as all shops sell, some of it is but i have seen some of the stuff that comes from ebay and seen samples of stuff from china. The poor stuff that we wont import is what ends up on ebay.....

TVL and resolution are two different beasts, and not related in any fashion.

TVL is determined by placing a chart in front of the camera with of course a bunch of lines. The number of lines that you can clearly distinguish before the lines become blurred is the TVL. If you search the forum for "TVL" and "interlacing" you will find a few more precise explanations as well.

Chaps, I posted this yesterday but for some reason the forum didn't take it. No doubt it was finger trouble on my part.

Thanks for replying, I really didn't expect any replies on new years eve!

James, the only reason I question the quality of UK goods is due to the fact that they look the same and have the same specs.

I know I shouldn't go on Ebay without having my hand held but I do believe that if a device says it is 480TVL then that is what it is ( i know all about the grey area of the definition of TVLs). Interestingly I did some digging on the camera and the sales pitch highlights the use of a sony CCD but the device pictured in the advert is in fact the CCD processor, who knows what the CCD is. Also the spec for the CCD in terms of effective pixels is the lowest i've seen for 480TVL.

Curtis, I ought to mention that the capture card is a kodicom 4400R which seems to work very well and as you know is bt878 based. But if the kodicom can capture 720x576 from my DV camcorder with no interlace problems then why not a camera that can do 480TVL. This makes me think that the camera does some simple line doubling internally to get the PAL spec. So apart from my camcorder has anybody used a (cheap < £100) 480TVL camera, or similar, at its intended resolution and got good results?

Lee, I haven't spoken to any dealers, which I know is bad, so perhaps I should and find out their returns policy.

At the end of the day all I'm trying to achieve is a domestic system as cheaply as possible that is effective. In all honesty it seems the inexpensive way to go is cheap cameras with the correct lens to get a good identifying capture.

As fas as being scammed on Ebay, I don't really think I've been scammed just duped a little. The camera is still quite good and no worse than which I could have got from the local DIY shops for the same money, in fact probably better. Just not what I paid for thats all.

In between the time that I wrote that little lot above and now I did some more research and found that my camcorder has a progressive CCD which of course means no line tearing. I am now satisfied as to why I can have line tearing on one camera and not on another. Of course the cheap camera has still got poor resolution. As cordel says TVL and resolution are different beasts, never the less this cheap camera has in way got the TVLs that it is sold as having. I have held it up to a grating and compared it against others and quite simply its no better than the 300TVL cameras I have.

Best Regards
John

you cannot compare anything by spec alaone. For example we only use branded equipment on our installs. just cos soething has a sony chip in it doesnt make it a sony camera. If i put ferriri spark plugs in my car i dont have a ferrari.

But regardless any interlaced cam will do what you are seeing. Regardles s of budget. 2 things srpint to mind.
1, your camcorder is outputting a non interlaced signal but i would have thought hat it will still be effected
2. You didnt notice it before.

We now use ip cams with progressive scan chips to stop this.

Hi James,

My camera is most certainly not sony but I was hoping the CCD would be.

As for interlacing the following thread describes the problem well especially the comment by kamand. I wish I had found this thread earlier.

http://www.zoneminder.com/forums/viewto ... einterlace

Any way my Camcorder is progressive scan CCD with interlace output. My understanding is this:

The CCD takes a progressive picture every 1/25 second and hence a complete picture every 1/25 second. The PAL output device reads the CCD memory using interlacing to read every other line thereby creating a standard PAL signal with interlaced fields at 1/50 second. The great thing with this approach is you get the benefits of progressive scan for the cheap (technically speaking) price of interlacing.

I just wonder if all camcorders that are able to take 'proper' photos to a memory card are progressive scan. it would make sense if they were.

Well I've now got that clear in my mind I don't know whether it will help any one else

John