HD versus IP - Removing the Smoke and Mirrors

Author: CCTV Supplies Category: TIPS Date: 2014-03-10 Hits: 2223 Comments: 2
With traditional analogue CCTV nearing the end of its life, the marketing war has begun between the competing digital technologies. Unfortunately, it's not always easy to make an informed choice.

For a long time now, IP based CCTV systems have established themselves as the go-to solution for high definition video when standard analogue footage just doesn't cut it. However, for the last couple of years, a new player has been quietly gaining market strength and will emerge as the predominant choice in TRUE high definition CCTV surveillance.

HD-SDI technology has been around for quite some time in television broadcast but only recently started to make its way into CCTV surveillance. Initially the cost was high and it couldn't make ground against the established IP CCTV market. However, as technology advances, prices become more competitive. In this post, we will outline the hidden truths that the IP movers and shakers don't want you to know.

CAMERA RESOLUTION

IP camera marketing strongly focuses on image resolution. It's common to see claims of 2, 3, 5, 10, 12 even 23 megapixel! Sounds great - more is better, right? Time for a reality check. More pixels means more data that needs to be pushed around the TCP/IP network. Typically the same network that your computers are connected to. Increased data flow results in congestion and ultimately slower network performance. Higher pixel count also has a negative impact on night performance as we will explain later. Additionally, storage requirements increase dramatically and playback/search performance suffers as there is more data to stream from the hard drive. Also think about backing up a few minutes of footage from 4 cameras to give to the police and you will think about buying shares in your favourite DVD media company - the police probably won't appreciate it much either....

In an effort to minimize the data amount, the IP camera applies compression algorithms to the image before streaming it to the recorder. This results in a degraded image with limited colour depth, meaning subtle tonal differences in the image gets averaged and substituted for a less defined representation of the scene. Below are images from a 3 megapixel IP camera compared to a 2 megapixel MHD HD-SDI camera.

 
3 megapixel IP

IP_Camera

 
2 megapixel MHD XU1 HD-SDI

MHD_HD_Camera

You can clearly see that the HD-SDI image has much better tonal range than the higher resolution IP camera, preserving the finer details. You might be thinking the difference is minor but it just shows that there are better alternatives to the IP dogma.
 

Remember when we thought these were cool?
...technology changes.

old-cellphone

 

RECORDING RESOLUTION

You've bought your 16 channel IP recorder, a stack of 3 megapixel cameras and you're all wired up ready to go. You set the recording resolution to 1080p for each channel and are wondering why your recorder is refusing to record. Many IP recorders will record at 2 megapixels (1080p) on one or more channels but begin to run into resource limitations once you start loading up the system with a hand full of cameras, requiring you to either reduce the recording resolution or bit rate (image quality). Often, multi-camera IP installations are downgraded to D1 resolution - the same resolution your old analogue DVR chugged along at for years. What value is your 5 megapixel IP camera now and where can I find a recorder for that 23 megapixel behemoth?

STORAGE

With higher resolutions come demands for more storage. Analogue DVRs are very efficient with storage usage. OK, they have a lower resolution but they can be configured to record at low frame rates when nothing is happening and then switch to a higher frame rate when they detect motion in the scene. You get the benefit of fluid motion when you need it with many weeks or even months of footage. It comes as a big surprise to learn that most IP CCTV systems are not capable of this. You need to configure the camera to either stream continuous video or only when motion is detected, it may not be capable of automatically switching between the two options. You need to decide what will be suitable for your application and stick to it. It becomes a trade off between performance or storage. Some higher end IP systems may have this functionality, but obviously you pay more to get a basic feature that really should be in all IP recorders.

NIGHT PERFORMANCE

All high definition cameras have performance problems at night. Currently there is no getting around this. It is a limitation of the light capturing properties of each pixel in the image sensor. The smaller the pixel, the less light it's able to sense at night. In simple terms, your 5, 10, 12 megapixel camera will become a lot more grainy at night than a 2 megapixel camera. In fact, in low light situations, you can get better performance from a good quality analogue camera. A case in point, all our NPR (number plate) cameras are B&W analogue - ideal for night time use. Cameras will compensate for low light situations by opening their shutter for longer exposures, thereby allowing more light to enter the image sensor. The downside to this is that any moving object will appear blurred. A 23 megapixel camera we once saw at a trade show had a maximum frame rate of 2 fps in the day! We didn't look long enough to even consider what it would do at night.

LICENSING

Here's a little sting that you won't know about until you try connecting that "bargain" IP camera you bought from another supplier. It just might not work with your recorder. The IP surveillance industry model is based on a captive market. There is a license requirement ($$$) for your recorder to be able to work with your camera.

When IP CCTV solutions first entered the market, only the processing power of a PC could cope with the data stream from the IP cameras. As we all know, computer software is easy to pirate, so to prevent this and protect their investment, the developers designed a license dependency model, meaning that pirating the software wouldn't do you any good without a valid license for each connected camera. If you buy your recorder and camera from the same supplier, the license is already included in the sale of the products. However, if you were to later add a camera from a different manufacturer or replace your recorder, you will most likely be unable to get them to work with your existing installation. You can sometimes resolve this by paying the supplier a license fee to unlock your device for use with your system. If you were replacing a camera, you will only need one license. If you were replacing the recorder, you might need to pay for a license for EACH camera you already own! Sometimes you might just be out of luck and have either manufacturer simply to refuse to provide a license for use with their competitors' product, forcing you to ditch your "bargain purchase" and return to your original supplier with your tail between your legs, wallet in hand.

As you can see, this model has great benefits for the IP CCTV distributor as it locks the end user in. This is why we believe there is heavy negativity from the IP camp when a competitive, lower cost "open" solution comes along. It deeply threatens their business model.

ANALYTICS

IP CCTV advocates will sell you on the virtue of being able to do analytics - missing object detection, people count, facial recognition and so forth. We've looked at some of these systems and would have to say the accuracy has been dubious at best. One system we tested insisted we had over 1000 customers enter our shop during the day! We wish. Obviously when relying on analytical data, any error renders the process completely useless. Another problem with these features is that they need to be defined prior to any recording taking place. You cannot add analytics after the fact, the data needs to be recorded with the footage. Facial recognition needs to be taught to the system - it cannot identify someone it doesn't know, and what happens when someone wears sunglasses or a hat?

IT INFRASTRUCTURE DEPENDANCE

By their very nature, IP systems are more dependent on extraneous hardware for them to function. Each camera connects back to the recorder via a switch or router. In some cases, the switch is built into the recorder. A failure in the switch or router will result in no video being recorded. In most cases the IP surveillance system is shared on the local network and therefore vulnerable to security breaches or attacks. Ideally, an IP surveillance system should be installed on its own dedicated network backbone but in reality this rarely happens due to cost.

Being IT based, IP CCTV encroaches the domain of the Network Administrator, who typically defends his realm with vigour and will make installation and maintenance difficult for the security provider, and rightly so. Both IT and security specialists have been trained in their respective fields and should not be involved in the other's business. Many times we have seen IP CCTV problems arise when either party crosses the divide and fiddles with things they know little about. It is our belief that CCTV should operate as an independent and secure system.

THE ALTERNATIVE

Our MHD Kratos HD-SDI or what we like to call TRUE HD recorders, are as simple to use and install as the old analogue systems we have been using for decades with the benefit of full 1080p resolution, the same resolution used in HD digital television broadcasts throughout Europe (Australian HDTV tops out at 1080i). There is no need to downgrade picture quality when you load up the Kratos HD DVR with cameras. There are no licensing fees - just plug in any HD-SDI camera and enjoy high definition CCTV video. The DVR is simple to setup, you don't need a degree in IT networking to configure the cameras or balance framerate/bitrate to stop the whole system from falling over. The HD system works independently from the network, meaning a problem with a switch or router will not render your surveillance system inoperable.

As with any product on the market, you can find quality items but there are plenty of lemons too. We've extensively tested many products and rejected most of them. Just because a product is HD-SDI doesn't mean it will perform well. There are a lot parts that make up a DVR or camera and the product is only as good as the cheapest component. Many times we have tested a good camera that has been let down with a cheap lens (our garbage bin is full of them). Also beware of cheap Chinese analogue based DVRs with a HD-SDI module bolted on. You see plenty of these on eBay - they just don't work.

Beware of cheap imports

This Chinese DVR would only record for a couple of hours at a time and then give up.

 

MHD Kratos HD recorders have been developed with proprietary mission specific ASIC processors at its core, giving it unmatched performance. You wouldn't expect Ferrari to drop an off-the-shelf engine into their sports cars - they build the engine specifically for the purpose.

Even the old adage "You get what you pay for" doesn't hold up any more. We have seen some expensive systems that just shouldn't be on the market. Our advice is to get a demo on the products you are looking to buy. A good salesman will always tell you what you want to hear but it's your investment, make the right choice. We are always happy to demonstrate our products because we have total confidence that there is no better solution when it comes to TRUE High Definition CCTV.

EASE OF USE

It's surprising how often functionality is not considered when deciding to purchase a DVR. When you boil it all down, the most important task the DVR will be expected to perform is to find the critical footage you need. We've seen it time and time again, everyone focuses on getting the cheapest system and never considers how it will perform. Picture this scenario, something has happened on your site but you don't know the exact time the event happened. Most recorders have very limited search and playback ability, typically just a calendar search. You will select a day and begin playback at an early time, pour yourself a cup of coffee, and stare numbly at the screen as you fast forward through a full day of footage looking for what happened. It's frustrating and time consuming. The Kratos has been designed to help the user find what they are looking for. There are a variety of search methods that can be used that don't require the user to stare at the screen. Simply set the search parameters and let the Kratos do the work for you. Hours or days of footage can be searched and presented in a thumbnail view without user intervention within minutes, allowing the user to attend to other matters, ultimately saving time and money.

 



 Kratos Museum Search - working for you
.

 

CABLE CHOICE

HD-SDI uses standard 75ohm coaxial cable as its transmission medium. That's the same cable that analogue CCTV uses, making retrofitting HD-SDI into an old analogue site very cost effective by utilising the existing cabling. Now, the IP advocates will be shouting at the screen "HD-SDI only has 60m range on coax!" This is true in some cases where the cable quality is not up to par, but there are solutions. There are low cost inline repeaters available that will allow up to 200m transmission on RG59 cable. Multiple repeaters can be daisy chained to reach greater distances. In most cases, the existing cable runs will be less than 60m. On RG6 cable you can expect to get up to 120m. IP installations are affected by similar limitations. The segment length of 100BASE-T Fast Ethernet is limited to 100m, requiring a switch to extend the run for another 100m and so on. The advantage is clearly in favour of HD-SDI, if the existing cable can be used, then you are saving money on cable and labour. If you need to re-cable (as you would have to do if upgrading to IP) then you can get greater distances with RG6 cable than you would with IP on Cat5e.

LOWER COST UPGRADE PATH

A great advantage of the Kratos HD-SDI solution is that existing analogue cameras can be used with the recorder, allowing for a gradual upgrade expenditure outlay. With a small, low cost converter, 4 analogue cameras can be recorded on 1 HD input. A number of installations we know of have taken advantage of this feature and installed 64 analogue cameras on one 16 channel Kratos DVR - a substantial saving.

You can do the same thing on an IP based system either by using a Hybrid NVR (typically a high end, high cost server grade PC with analogue capture cards installed) or buying an analogue to IP converter for each camera - don't forget to add the license fees!

THE BOTTOM LINE

If you've made it this far, it's obvious that we strongly believe the Kratos HD-SDI solution is far ahead of the IP alternative in regards to image quality, initial and ongoing costs, and ease of installation.

But most importantly, and typically ignored, ease of use for the end user! We feel that for too long, the needs of the end user have been ignored and they often don't get what they really wanted. This is evident in how CCTV products are marketed to the public and let's face it, the end user is not an expert in the field and relies on advice given to them from their security provider. It is for this reason we feel the need to expose the unspoken truths about IP based CCTV systems so that the end user can make an informed decision.

 

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Comments

Date 2014-08-26 10:05:54 Posted By CCTV Supplies Comment Link
Thanks for your comment Rex. I'm glad the article was of some use to you.
Date 2014-08-25 13:10:27 Posted By Rex A Comment Link
Good article and helps fill in some of the blanks. Was having difficulty deciding between IP based system with a NVR and a conventional system with HD cameras and coax cable. Article helped a lot and have come down on the side of HD cameras, coax and dvr system. Cheers Rex A

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