IP camera question

[admin]

I hope I am posting in the right forum


Anyway , I bought an IP camera , nothing too exciting just a chinese one with pan , tilt and zoom. It states a frame rate of 25 FPS PAL and 30 FPS on NTSC.

It works either wired or wirelessly but the frame rate is no where near those figures. I pretty much get the same from either , around 6 FPS unless I extend the wireless to the point of a very poor connection in which case its very low.

I have no idea about FR's and how they work. Can anyone explain to me in laymans terms as to why the FPS rate is nowhere near what they state ? Does it have to do with what speeds my LAN can operate at ?

Thanks in advance for any answers.

[intelliGEORGE]

Got specs on the camera?

Quite possible the image quality is large so it sacrifices bandwidth instead. Are there any settings in the camera?

12FPS (frames per second) is equivalent to the speed of the human eye, anything less and it becomes noticeable, anything more is a waste really.

[admin]

Thanks for the reply intelligeorge.

Yes there are a few settings in regards to display such as VGA , QVGA and a few others. I just had a fiddle with a few and noticed that the frame rate does go up with others. I have been using VGA.

[CCTVguru]

most lower cost products and for that matter several high end products can not maintain 25ips at full quality. Drop your resolution to QVGA and see what happens.

[intelliGEORGE]

Ok so lets establish how big the file sizes are.

Firstly, there are 16bits per pixel, and because there is 8bits in a Byte, each pixel is 2Bytes.

VGA is 640 x 480 pixels = 307,200 pixel.

Now that we have established that each frame (VGA setting) is 307,200 pixels, we now times that by the amount of bytes per pixel.

307,200 x 2Bytes = 614,400B or 614.4kB

So each frame is 614.4kB @ 640x480 resolution.

614.4kB @ 25fps = 15,360kB (15.3MB) per second data transfer.

Now if we wanted to pump this data on a 100Mbit LAN we will soon find that we have exhausted the bandwidth.

15.3MB x 8bits = 122.4MBits/second

So in conclusion you will not be able to stream @ 25fps unless you have a Gigabit LAN.

[intelliGEORGE]

Even at QVGA (320 x 240), unless the camera has built in compression codecs, you will still chew up bandwidth @ 25fps.

Take my last result and divide by 4 (QVGA = 1/4 VGA) and you will get 30.6Mbits/second.

[admin]

Its not an issue as it is , as I am happy enough with the product. It was more a question of curiosity than anything else.

Thanks for the replies , it seems the display settings are the answer to my FPS query. I am running it through a laptop connected to a 22" LCD monitor so I will have a fiddle around to get it the best I can for full screen.

Thanks for the detailed reply intelligeorge

[Chimp]

Good post George very informative.

[intelliGEORGE]

No probs, let us know how you get along with the settings.

[Privatteer]

George, did you slip a decimal point somewhere? Framesize seems excessive even for Jpeg. Below values are what I noted for a camera I used a little while ago.

JPEG VGA (640x480) 25FPS Framesize 63.476 kB bandwidth 12.397 Mbps
MPEG4 VGA (640x480) 25FPS Framesize 13.671 kB bandwidth 2.670 Mbps

Sanity:
As you worked out a lot of camera do not support full framerate at full resolution. It is either 1 or the other.

[intelliGEORGE]

Framesize seems excessive even for Jpeg. Below values are what I noted for a camera I used a little while ago.

JPEG VGA (640x480) 25FPS Framesize 63.476 kB bandwidth 12.397 Mbps
MPEG4 VGA (640x480) 25FPS Framesize 13.671 kB bandwidth 2.670 Mbps

That's all good and well if I was using JPEG in my calculations. JPEG is a compression standard, I was working on raw bits.

I don't know what camera he has, but my calculations are for converting pixels to bytes to understand how big 1 frame is before we compress it to many different forms.

[intelliGEORGE]

JPEG VGA (640x480) 25FPS Framesize 63.476 kB bandwidth 12.397 Mbps

JPEG compression ratio is 10:1, so the 63.476KB JPEG's original size would have been 634.76KB before compression.

[Moof]

Hi Sanity.
I am looking at a IP camera, Where did you get it and how much?
Do you have a link?
Thanks

[admin]

Hi Sanity.
I am looking at a IP camera, Where did you get it and how much?
Do you have a link?
Thanks

hi moof

This isnt the seller i bought off but it is the same camera


I got it 3 days after ordering it from china. You can operate it via its own webserver by logging in to it with a web browser such as 192.168.0.5 or whatever on your own lan. It also operates via third party software. You can operate it either wireless or with wires , it takes a standard USB wireless dongle. It has motion detection and can record in a number of formats including .avi and .wmv .

If you want anymore information let me know as the brief descriptions they give dont really cover it. I can also send you a link for a look when i get off my arse and setup port forwarding so it can be accessed over the internet.

[Privatteer]

614.4kB @ 25fps = 15,360kB (15.3MB) per second data transfer.

Now if we wanted to pump this data on a 100Mbit LAN we will soon find that we have exhausted the bandwidth.

15.3MB x 8bits = 122.4MBits/second

So in conclusion you will not be able to stream @ 25fps unless you have a Gigabit LAN.

Well no cctv camera I know off transfers in RAW, even the cheapest uses Jpeg or some version of Mpeg2/4.
In Sanity's case its a little irrelevant unless you apply a compression standard to it.
It does make a big difference to wether or not he is exhausting his bandwidth.