Bandwidth consumption

[Pearl 0]

I'm setting up a T-1 remote monitoring station for our DIVAR systems and I'm an extreme novice. What is most important to me now is how to determine the bandwidth consumption that the video streaming relay from each of my DIVAR locations to the remote monitoring location. If I view live streams simultaneously, how much bandwidth will that consume? Is there a general value that I can use?

[cctv_down_under 0]

There is no general rule because all products use different technology's and codecs and compression.

 

Geovision allows you to set the amount of traffic (video data) that is sent so basically you are setting the bandwidth to suit your application (size of your pipe)

 

The more cameras you view at once the more consumption of your bandwidth will take place, you can also use what is known as packet shaping to limit the amount of bandwidth.

 

The things to look for are bandwidth throttles on the softwrae and software that allows the compression on the fly which means you can watch a lesser quality picture at a faster speed. I would say that most importantly you want a system that will do MPEG4.

 

Like rolling film through an old projector the video is made up of many still shots but with MPEG4 then you only send (refresh) the moving bits this makes it faster because it is smaller, for example:

 

Imagine a camera viewing a game of tennis, the players will move constantly so every picture is different so every sequence is made of many pictures, what MPEG4 will do is keep the image of the court and not bother drawing it again on the next picture and will only draw the moving bits, like the players and the ball, this means it only needs to send, comprress or sample 1/8th of what it would have to have done if it needed to draw the court again.

 

The best bet would be to connect to one camera and just measure your download... make sure your T-I supports free uploads or it will be a big bill also make sure the video data between the two sites is free and not counted as a download because if with the same company they should not have to pay for it.

 

I hope this helps.

[Joebo 0]

The quickest way to determine the bandwidth would be to multiply the average image file size x number of images per second x number of simultaneous remote users.

 

For example, the DiVar has average file sizes of 16K, 24K or 40K, can record up to 60 images per second (ips) * and can have up to 6 remote users communicating with 1 DiVar system **. Therefore, worst case would be 40K (file size) x 60 (ips) x 6 (users) = 14.4Mbps

 

* The unit records up to 60ips, however, I'm not sure if it can transmit up to 60ips over the network. NOTE: The units do have a bandwidth throttle that allows you to limit the amount of bandwidth the system will use. And, you can also limit the amount of user per system.

 

** 6 is the max. number of simultaneous users communicating with 1 DiVar system. So, with 3 systems you could actually have 18 users on-line simultaneously (6 users per system).

 

One last thing to note is that the bandwidth is only being consumed when connected. If you intend to be viewing video 24/7, you'll consistently be using a lot of bandwidth.

 

For more info go to www.boschsecurity.us or call 800-326-3270 or 717-735-6300. They probably have a document that they can send to you.

[Pearl 0]

Many thanks for the advice and information. I very much appreciate your generosity and helping me get up to speed.

 

I hope to attend some trainng soon....company will pay for it. That and this forum, I believe, will help me become more familiar and competent faster. Again, many thanks.

[DavidR 0]

Joebo explained it very well.

 

Any system will give you control over your bandwidth usage, either with a single bandwidth control, or with controls like image size, frame rate, etc.

 

So you can use as much or as little bandwidth as you need. You just trade off fps and/or image quality for bandwidth.

 

MPEG-4 will get you much smaller image size (because it onyl sends changed, and rarely sends complete images), hence more FPS pre given bandwidth. Other compression mechanisms do the same thing different ways--they give you more quality or more fps in less bandwidth than uncompressed images.

[pinchio 0]

The easiest way is to use a bandwidth calculator specifically designed for DVRs.

 

March Networks a manufacturer of DVRs has built a awesome dvr calculator which includes calculations for storage requirements, download times and bandwidth requirements based on their DVRs.

 

check it out: http://www.marchnetworks.com/products/calcregform.asp