Why some of the IP camera has 540TVL?

[mujju_433 0]

I have seen in some of the IP cameras where the resolution would be VGA , so here in the specifications of IP camera , it shows 540 TVL why so , According to my knowledge TVL should come only in Analogue cameras am i right?

 

or the answer is related to VGA , when we are talking about VGA display IP camera, does 540 TVL comes into account????????????? Please clarify

[jeromephone 6]

If you take a regular camera and run it into a video server it is still and analog camera some of the older IP camras were analog cameras with a NIC card I have a couple of Bosh cameras like that they have a good picture but are still analog.

[Soundy 1]

...or if the camera has an analog output, it could be referring to that.

 

Or it could just be a marketing thing because they think their customers expect to see such numbers (maybe they've even been asked by some customers what the camera's TVL rating is)... or they could just have clueless people writing their specs and ad copy.

[mujju_433 0]

Hi Soundy/Jeromephone,

 

Could you please clarify me , How can they do marketting if the IP camera doesn't require to have TV lines on it........Some of the IP cameras will have Analogue Output but that is just to check the ip address and the video would last on the monitor for about 10 minutes , after that the video disappears. So now tell me the clear answer why do TV lines come into picture when talking about IP Cameras?

 

Regards

[tomcctv 190]

ome of the IP cameras will have Analogue Output but that is just to check the ip address and the video would last on the monitor for about 10 minutes , after that the video disappears.

 

 

i think you are talking about the setting up of a PTZ camera that then uses an encoder.

 

 

if you see ip cameras listing 580tvl -600tvl then they are cameras with encoders. you will also see webcams being sold as ip (vga) the cheap end of the market. if you want to go ip then dont go below 1.3mp

[Soundy 1]

Hi Soundy/Jeromephone,

 

Could you please clarify me , How can they do marketting if the IP camera doesn't require to have TV lines on it........

Because some people expect to see a TVL number when they're shopping/comparing CCTV cameras. If they're looking for it on IP cameras, it probably means they don't understand the term anyway and are just looking for the highest number because "it must be better"... nevertheless, it's not uncommon for marketing people to use irrelevant information in their copy just because they know people expect to see it.

 

Some of the IP cameras will have Analogue Output but that is just to check the ip address and the video would last on the monitor for about 10 minutes , after that the video disappears.

Some do have full-time analog output that can be used to feed a live monitor... for example, the customer-awareness monitor you see when you enter a store, displaying the camera that watches you as you enter.

 

So now tell me the clear answer why do TV lines come into picture when talking about IP Cameras?

There is no "clear answer". We've given you some reasons WE think this particular manufacturer MIGHT have listed it. If you want to know the actual reason, you'd have to ask their marketing people.

[SportPlumber 0]

Well I guess it depends on what you are used to. As an old Broadcast TV guy I can tell you that TVL is a measure of camera image resolution usually measured by correctly framing the resolution chart and using a monitor to determine the number of visible "Lines" in both the vertical and horizontal axis.

 

To me it seems a more useful way to specify image resolution than saying simply "VGA". VGA is a display format and really doesn't tell you much about the sharpness of the image. Or more specifically the camera's ability to discern fine detail.

 

It is probably true that the marketing folks just want to throw out numbers and it is a carry over from pre- IP Cameras. But it is not related to Analogue or Digital formats. It is a way to measure camera performance. Since there does not appear to be any universal adoption of this or any other method to rate the IP Cameras by manufacturers at present, it does unfortunately seem useless.

[ando 0]

Here is an article that explains why TVL is important even for IP cameras and how TVL can help you determine which multi-megapixel IP cameras are actually providing a good video quality.

 

http://www.acti.com/KB/detail.asp?KB_ID=KB20101020001

 

The last chapter of the article explains how you can measure the TVL value of each camera by yourself, which also means that you can validate which manufacturers are providing true numbers.

 

I hope it is useful! Thank you!

[Soundy 1]

Well I guess it depends on what you are used to. As an old Broadcast TV guy I can tell you that TVL is a measure of camera image resolution usually measured by correctly framing the resolution chart and using a monitor to determine the number of visible "Lines" in both the vertical and horizontal axis.

 

To me it seems a more useful way to specify image resolution than saying simply "VGA". VGA is a display format and really doesn't tell you much about the sharpness of the image. Or more specifically the camera's ability to discern fine detail.

Since IP cameras output a data stream and not (primarily) analog video, "VGA" *is* a valid spec, since "VGA" also indicates 640x480 pixel resolution (along with terms like "WVGA" (wide-VGA, or 800x480), "SVGA" (800x600), "XGA" (1024x768), and so on (see http://en.wikipedia.org/wiki/Graphic_display_resolutions for more).

[SportPlumber 0]

You are correct that VGA and the variants are valid specs when looking at IP Cameras. My point is that it doesn't tell you much about the quality of the camera's image. TVL on the other hand is directly related to the camera's ability discern detail and also a "valid" spec.

 

It is just as valid with IP Cameras as analogue since it is simply an empirical measurement of image performance. Certainly there are many other aspects to consider such as frame rates, sensitivity, enhancement color rendition to name a few. But I disagree that one "doesn't understand the term" if they are using it in conjunction with IP Cameras or any camera.

 

Regards

[mujju_433 0]

Thanks a lot everybody for clearing my doubt

[Soundy 1]

You are correct that VGA and the variants are valid specs when looking at IP Cameras. My point is that it doesn't tell you much about the quality of the camera's image. TVL on the other hand is directly related to the camera's ability discern detail and also a "valid" spec.

In theory, sure... in reality, the term has been so abused by offshore manufacturers it rarely has any sort of direct relation to actual output. Plus, as has been noted here many times, there are so many other factors that come into play in determining a CCTV camera's actual output quality - post-processing, component quality, design quality, build quality... optics are especially critical (cheap single-element plastic lenses vs. well-built coated multi-element all-glass lenses, for example).

 

And there are times when higher TVL can mean lower performance elsewhere - the higher the resolution, typically the poorer low-light performance you see... and LUX specs on CCTV cameras are just as fudged and meaningless most of the time.

 

But I disagree that one "doesn't understand the term" if they are using it in conjunction with IP Cameras or any camera.

I only listed that as one possibility as to why marketers may include it... and yes, it is a very real possibility.