Should You Use Video Encoders?

•Published Mar 18, 2009 00:00 AM

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Many people want to go IP but 95% of deployed cameras are analog. Encoders are the most common solution but is that the best approach?

What are Encoders?

Encoders are appliances that convert analog video feeds to digital so that the video can be transmitted over IP networks and stored on digital storage like hard drives. Encoders generally cost $300 USD to $400 USD per analog camera.

While DVRs encode and store video, encoders simply encode video and transmit the video to a remote storage location. If you are not familar with encoders, I recommend a very good encoders tutorial from SDM.

Axis Makes the Case for Encoders

In a recent whitepaper on encoders [link no longer available], Axis recommends using encoders as "the easy path to network video."

In it, Axis dismisses DVRs as an alternative, saying:

"[DVRs have] never been able to deliver more than a handful of the benefits that can be provided by full-fledged network video systems. With DVRs, video is still stored on proprietary equipment, which makes integration with the fast-growing market of software applications for network and video management."

We have 2 claims: (1) a general claim about lacking benefits and (2) a specific claim that DVRs do not integrate with software applications.

The Key Need for Encoders

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Encoders have clearly been the best and most frequent option for migrating to network video. I see two practical reasons:

DVRs generally did not support IP cameras
IP Video Software generally did not support video stored in DVRs

It's the combination of these two factors that makes designing systems so difficult. On the one hand, if you connect analog cameras to a traditional DVR, you are stuck with not using IP cameras. On the other hand, because IP Video Software has very limited support for DVRs, you cannot integrate your analog cameras connected to a DVR with your IP cameras.

What's Not a Barrier

Other technical elements in using DVRs or IP video software are generally not a barrier. Both DVRs and IP Video Software offer significant capabilities in access control integration, remote viewing, client UIs, PoS/ATM support, mapping, analytics, etc.

Use Encoders?

In the old days, you had to use encoders because of these two historical barriers. They were used despite the fact that separating encoding from storage almost always significantly increased the cost, complexity and service requirements of deployments.

The big challenge with encoders is the separation of encoding and storage into separate devices. Relative to doing both together, it requires:

Setting up a network between the recorder/storage and the encoders
Configuring the encoders AND configuring the recorder
Physical set up and power to both encoders and recorders
Purchasing two sets of products that cost more than buying them as a set
Multiple IP addresses
Knowledge/training on both encoders and recorders

One interesting cultural difference is the perceived 'pain' between traditional security vendors and IP video integrators. Many IP video integrators, who have never used a DVR, think that there is no pain at all and that setting up encoders and IP video software is not any harder than a DVR.

As someone who has an IT background and has set up many DVRs and IP video systems, IP video software and encoders requires many more steps and skill than DVRs. This is especially problematic when you try to do large roll outs requiring many techs in distribtued locations.

Economic Trade-off Between Encoders and DVRs

16 channel DVRs and 16 channels of encoders are generally close in price. On a per channel basis, they both are in the range of $300-$400 per channel (a 16 channel 'enterprise' DVR costs $5,000 - $7,000).

The benefit of the DVR, of course, is that it eliminates the issue listed above, includes the video management functionality and storage. When you add that in, the cost reduction can be significant ($100 - $300 savings per channel).

How Recent and Upcoming Product Releases Impact

A major shift has occured -- Hybrid DVR systems are becoming very common. In 2006, hybrid systems were few and far between. Now, most DVR manufacturers offer hybrid support. While some DVRs have limited hybrid support, many are now full fledge - as examples, Exacq and Digiop, who we recently examined in the 2009 DVR Comparison Guide.

Hybrid systems eliminate the problem that DVRs restricted one to analog only systems. With hybrid, you simultaneously:

Reduce cost for supporting analog cameras (by eliminating encoders)
Yet retain flexibility to use wide varieties of IP/megapixel cameras

The other trend is for IP Video Software to support DVRs. This is a trend that I think is farther out but one that is worth carefully watching. OnSSI is the company making the most 'noise' on this front. They have designed their new Ocularis to support integration with 3rd party DVRs [link no longer available]. The significant problem here is that they have not announced any specific DVRs that they are supporting. Until they do so, it's not implementable and does not help deployments.

IP Video Software integrating DVRs provides significant customer value but faces two more problems: (1) DVR companies are likely disinclined to let IP Video developers integrate with their systems. By not allowing others to integrate, DVR vendors can push customers not to migrate. (2) Supporting third party recorders can cause technical issues depending on the type of CODEC used, the means to store, how motion detection is performed, etc.

On the other hand, because camera manufacturers are now adding on-board storage, IP Video Software providers are increasingly being asked to add support for remote video storage. To the extent that IP Video providers do this, this would provide the technical foundations to increase support for DVRs.

Nonetheless, hybrid DVRs are the key tool TODAY for eliminating encoders. In the future, IP Video systems supporting DVRs may be a way to eliminate encoders and provide a more seamlessly integrated solution.

Application Best Fits

The most important and basic criteria for choosing encoders is whether your VMS system supports hybrid DVRs. If they do not, you have to use encoders. Since many VMS do not, encoders will be your only choice.

For those using VMS systems supporting hybrid DVRs, the decision should then be made based on how many analog cameras are located in close proximity to one another. Specifically, the key element is where the coaxial cables are terminated (or can be terminated). If there are 8 or more analog cameras than can be terminated in a single location, a hybrid DVR is likely to be more economical. Fewer than this and an encoder is probably better.

Of course, in any application where the encoders would need to transmit over a low-speed Wide Area Network (like DSL, Cable Modem, T1), using a hybrid recorder is ideal (because you will need to record on-site anyway).

Evolving Strategies

IP manufacturers and integrators need to accept that hybrid systems are playing a greater role and that adding support for DVRs can be advantageous.

Encoders are not really the easy choice. They simply were the only choice for a long time.

Supporting DVRs and using hybrid DVRs does extend the life of analog. To that end, it is not ideal for IP vendors. On the other hand, it provides a greater opening for IP to grow than the alternative of simply staying stuck in analog.

IP vendors should come to accept and embrace the role of these encoder alternatives as ways to stimulate broader accept of IP.