Wednesday, November 14, 2012

Viewing Your IP Cameras on Your Smart Phone

Recently there was an article in the IEEE technical journal that declared, “Video Telephony has Finally Arrived”.  They described how the Jetsons first predicted this in 1962, and now we can use our computer and Smartphone to do exactly what George did with his boss Cosmo Spacely.  This animated sitcom described the world in 2062.  I guess we did this sooner than expected. 

To make the video phone a reality a number of obstacles had to be overcome including cost of the video equipment, the cost of high speed connection, and better compression schemes.

Now what about viewing our IP surveillance cameras remotely?  Does the new technology allow us to view all our surveillance cameras at home or on the road?  Well almost.  When we use our Smartphone’s to see each other, we are usually just looking at a person’s face.  If we try to view a wider area, say the complete room, things are not that clear.  The video we see on our Smartphone has less resolution than that usually required for surveillance.  Because we would like to see a lot more detail for our surveillance applications we require much higher resolution and a better display.  A computer is still the best way to view your remote IP cameras.


Viewing an IP Camera using your Smartphone
Let’s look at the complete communication channel required to get the video from our cameras to our cell phones or even to a remote computer.  You can picture the components of the system as a set of water pipes connected together.  The bigger the diameter of the pipe the more water can flow.  The smallest diameter pipe will determine how much water flows through the complete system.  There are basically 4 components to the system. 

1)      First is the IP camera.  It needs to compress the video so that it uses as little data as possible to see the video without reducing the resolution. 

2)      Second the outbound bandwidth available at our cellular modem must be high enough to handle the data flow we need.

3)      Third the phone company cellular system must have enough bandwidth.

4)      Finally the Smartphone has to have good enough performance to support the latest cellular services and be able to display the video.

For example, if the bandwidth from the IP camera is 1000 K bits/sec but the cellular network bandwidth is only 200 K bits/sec. the maximum bandwidth through the complete system is limited to 200K bits/sec. 


The first IP cameras used MJPEG compression, and this is still the best compression for viewing the video on your Smartphone.  Today the new H.264 compression dramatically reduces the bandwidth required for an IP camera.  It reduces the bandwidth and the storage required over a factor of 10X. For example, a VGA camera (running at a frame rate of 20 fps), using MJPEG compression, requires about 4.8 Mbits/sec, while an IP camera using H.264 compression would require less than  400 Kbit/sec.  This compression scheme is dependent on many different factors including the amount of motion detected, so it is possible to use a lot less bandwidth. Take a look at our article about the
Latest H.264 Compression for more about this.

Cellular Network

One of the limiting portions of the communication channel is the cellular network.  This is usually the smallest pipe in the system.   3G networks provide a maximum of about 200K bits/sec bandwidth.  Since Smartphones do not work with H.264, there is a lot more bandwidth required for MJPEG.   Since we require 4800 Kbit/sec (using MJPEG compression) to see the video running at 20 fps, we will see a lower frame rate at our Smartphone because of the cellular bandwidth limitation.  In this case, we will get about 1/24 the frame rate or less than 1 fps at the phone.

 4G networks promise to increase the bandwidth to 1 Gbits/sec.  This should allow us to support higher resolution cameras.    I say it should work, but the reality is that cell phone providers need to share bandwidth with all the available users.  They will throttle the bandwidth used by that camera location whenever many people try and use the same tower connection.

Another important aspect of using cellular systems is the cost of the cell service.  You will have to purchase a data package from your local cell phone provider.  There are sometimes limitations to the bandwidth that they will provide.  

Viewing Many Cameras on Your Remote Computer
 When we use a remote computer that’s attached to the internet, there are four things to consider, the compression from the camera, the outbound Internet connection, the Internet speed and the inbound Internet connection.

Many Internet connection companies provide good inbound bandwidth but much less outbound bandwidth so always check.  The outbound Internet bandwidth can dramatically affect the frame rate you can see.  If your provider only gives you an outbound bandwidth of 512K Bits/sec, you will see a much lower frame rate at the remote viewing point. 

The best way to view multiple cameras is to utilize a viewing client that comes with Video Management Software (VMS). This also allows you to view recorded video as well as the real time video.  Ocularis from OnSSi provides an excellent client viewer, while TruViewIP
provides a good web client as well as a Smartphone interface.  The bandwidth to the remote viewing client depends on the total number of cameras you are trying to view, so the total bandwidth through the system available becomes very important.  If you have a limited bandwidth at any point in the system, you will see reduced frame rates.

Some of the same technologies used by our Smartphones to create a video presence are used by our IP camera systems. You can view IP cameras using your Smartphone, but you can’t expect full frame rates because of limited bandwidth through the cellular phone system.  To view recorded video or and view multiple cameras you will need Video Management Software.  You will also need more bandwidth when you view multiple cameras.

If you need help figuring out the best solution for your application, please contact us at 1-800-431-1658 or 914-944-3425 or use our contact form.

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