Subscriber Discussion

Should I Decode IP Cameras To Integrate With An Existing Analog System?

Are these a good option if a customer wants to add IP cameras to an existing analog system or should we avoid decoders?

As John notes, the purpose of the analog output varies with the camera. When I first saw this on an IQEye IQ511, the analog output had a "focus aid" overlay (basically the central area of the view was a 100% crop, while the full view surrounded it), and the analog output turned off after 5 minutes.

On the other hand, I've had several IQA11 domes on various sites with the analog output driving an analog-in customer awareness monitor, running 24/7 for 3+ years, with no issues. I've also replaced existing box-type ID cameras in a couple sites with Dahua 3MP box cams, running the analog out to an existing CA monitor (in one case, still the original 20" Panasonic CRT!), and they've been working fine for several months now.

"GE Truvision 1.3 MP camera" are in fact HIKVISION cameras. That's why the are working so good with DM or NUUO. :D

If you really need to install IP camera with IP trasmission but with analog signal output at the end I would recommend o use HIKVISION cam and their decoder of DS-63xx serie. But you must be aware that you can not downscale HD signal to BNC - rather use 4CIF on both digital and analog platforms.

There is also option of Sony hybrid cameras - they have analog and IP signal in signal coax output. To retrieve pure analog and transmit IP via UTP Ethernet network you need special decoder unfortunatelly. It is not cheap solution.

Matt, good point.

Some IP cameras are designed such that analog out just for focusing, others are for full time output (while streaming out an IP feed). It is important to check the manufacturer's implementation if you want to use both at the same time.

Mr. Lindgren is absolutely right. Analog cameras to analog monitors will always look better than a decoded IP stream to an analog monitor.

The same is true when encoding analog cameras feeding into an all-IP VMS. That's the downside to upgrading a customer to IP and then using encoders on their existing analog cameras. Then moving them from a 9" analog monitor to a 17"+ computer monitor will make it seem even worse.

Always laptop demo an encoder to the end user so they know what to expect.

By the way, there is a downside to our choice: analog cameras can display far better images on analog monitors than on a digital display via encoders. The encode process itself limits resolution and adds encoding artifacts. To minimize the degradation, we specified higher bitrates than the VMS manufacturers and Integrators recommended based on our system evaluation tests. Most manufacturers and Integrators recommended 2Mbps while we chose 3Mbps for around half of our cameras and 2.5Mbps for the rest. Our tests of several encoders revealed diminishing improvements above those bitrates.

Of course the downside to our choice was increased storage requirements.

We looked at both the analog/IP camera option and the decoder option ourselves but decided the cost and limitations of decoders and the need for two transport paths outweighed the ability to retain our analog matrix. Decoders are at least as expensive as encoders and we found that typically we would have to match them to a system. In other words, we couldn't use manufacturer A's decoders on manufacturer B's NVR/VMS. Decoders also add latency just as encoders do.

In the end, we chose to deploy a hybrid system, using encoders for our analog cameras and recording IP cameras' streams directly through the VMS.

I don't think it could cause failure, it's just that you will have poor quality

I have been told that the analog outs on IP cameras are not for constant use (only for focusing etc). If you use them on a permanent basis do they cause problems/failure?

An IP camera with an analog out lets you get 'regular' analog quality now and then, at some point, in the future, when the backend is upgraded to use the higher resolution IP 'out'.

I have a client using a GE Truvision 1.3 MP camera that does offer the analog bnc output that (Undisclosed (#0021312) Manufacturer referenced and it does work with a Dedicated Micros DS2 on the analog side and Nuuo Solo on the IP side at the same time. I'm not sure if this helps you get where you're trying to go. Hope it helps.

Timothy, you're like Captain Kirk, changing the rules here! :)

That said, if they can switch out the box, that would work best. Presuming they need to keep it, they are limited to the options above.

Maybe consider a hybrid recorder.

Another option would be to use an IP camera that has a full-time analog output.

John, thanks for the clarification!

The problem is a combination of wasted cost and reduced quality.

You have an IP camera that costs more than an analog one plus you then add in a decoder, which adds further cost.

By contrast, you can't get HD at all and once you decode and re-encode, even if you encode at 4CIF, it's probably going to look something like 2CIF (roughly) due to the loss in this process.

George, who's the DVR supplier? Many if not most DVR suppliers now offer NVRs that can be viewed from the same manufacturer client. That's your best option.

No other options at the moment. Just curious of how well decoders work with IP camera's and its video quality.


Additionally to what Jeremiah stated, is this process of lowering the video quality so much that it's simply not worth it?


George and I tried to use an axis decoder and camera with the VMS running on a local NVR to send the analog feedback to the customer over coaxial wire so they can just add into the screening room.

The problem was that the VMS took over the decoder and caused it to malfunction, so after 2 days with VMS support and no luck we gave up on using inside of the VMS.
Our customer just wanted to add a few new cameras at this time and was not looking to upgrade the entire system, but wanted the new technology to use.
What options do you have? As John says, the only workaround that I imagine is to integrate the ip camera into a nvr of the same manufacturer. But if you are talking about an analog system. I don't think you have that option...

In general, avoid decoders. The problem is that you have to decode the video and then re-encode it. That process losses quality. Plus, of course, one is constained to the quality of the existing analog system's encoding (which is typically not great, certainly compared to the resolution/quality of modern HD IP cameras).

How big is the system you are dealing with? Does the manufacturer offer an option to add IP cameras to an NVR and then display it on the same management software (i.e., the client can pull video from DVRs and NVRs)?