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Should I use a IP or HD-SDI for HD Recording?



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IP vs HD-SDI – The FAQ

There is a new competitor in the field of HD Video Surveillance Systems, HD-SDI.  We personally had a lot of questions about HD-SDI and we’ve had many from both installers and end users.  We put together some of the most common and critical questions comparing HD-SDI to IP systems in order to make it easier for you to make the decision.

So without further ado, here’s the FAQ!

Q. Is HD-SDI less expensive than IP?

A. Not necessarily, let’s look at a simple 8 camera system.

In this case, IP is actually about $175 less than the HD-SDI system.  This may come as surprise to a lot of people, but there is an easy explanation for it.

The key thing to look at here is the difference between the NVR and DVR’s price. The HD-SDI DVR is more complex to manufacture and requires more components to operate than than the more simple and efficient NVR.

The technical reason for this is that IP cameras have built in h.264 compression on the camera unit. With HD-SDI this must be done on the DVR itself, meaning it needs a higher performance processor and more complex components, driving up the cost of the unit.

So despite the HD-SDI cameras being less expensive than the IP cameras, IP actually slightly edges out HD-SDI in this price comparison. Not all cases will be typical. In some cases HD-SDI may be less expensive, in others IP is going to bring you a better price. If you’re interested in HD it’s worth checking out both or requesting a quote with both options from SCW.

Q. Which has the better image quality?

A.  IP wins in resolution, but HD-SDI has advantages.

HD-SDI currently maxes out at 1080p or about 2.0MP. IP cameras can go beyond 1080p HD, some of our IP cameras come as high as 5MP, or more than double the resolution of 1080p. So in raw resolution the IP cameras win out. You’ll be able to see more details and the video quality will generally just be sharper.

However, HD-SDI also offers some advantages, it lacks the potential packet loss issues that can occur on IP cameras.  It’s also a dedicated installation, so no network issues will impact the system.

Another advantage of HD-SDI is that the cameras send uncompressed footage to the DVR. What that means is you’ll get a very clear and crisp image in live view, however, recordings and playbacks are compressed.  If live view is an important aspect of your security system, HD-SDI might be a better choice.

Q. Is HD-SDI easier to install?

A. It depends on where it’s being installed.

While HD-SDI is backwards compatible with currently installed coax, Our HD-SDI cameras require 1Vp-p, 75ohm coax. Image quality and length will vary depending on the quality of the coax. HD-SDI also has length restrictions of around 125-150 meters or about 400-500 feet without a signal enhancer, and this can vary depending on quality of coax.

In situations where length isn’t an issue and the wiring meets the requirements, HD-SDI is a good choice for those who want to quickly upgrade from SD to HD. Replace the cameras and the DVR and you’d have a full HD system without having to run new wire.

HD-SDI carries near identical installation steps as regular analog CCTV, so it carries a familiarity with long term installers or current users and an ease of use for new ones.

However IP has some advantages as well, only IP cameras can do wireless, and with POE (Power over Ethernet) all you have to run is one cable. Overall, it’s going to come down to the individual situation and goals for the future capability of the job.  Another advantage of IP is that Cat5 is increasingly more common in buildings. If your building already has Cat5 installed this can dramatically quicken the installation job.

Q. Which has better operability with analog?

A. Surprisingly, IP!

Despite HD-SDI having the same RG59 connectors as analog the signal is totally different.  HD-SDI sends a digital signal, so you can’t just plug in an analog CCTV camera into a HD-SDI DVR.

IP has a few other options, you can pick up one of our Ambassadors, a hybrid DVR/NVR with equal slot numbers.  This allows you to use both on the same system. This can be useful in many different situations.  For example, we’ve built hybrid systems for people who have both high importance areas and low importance areas.  They wanted the absolute best image quality possible on the high importance systems, but didn’t want to have to pay the premium on the places of lower importance. A hybrid system was able to do this for them.

Q. Can HD-SDI do wireless like IP?

A.  No, only IP can do native wireless.

Like analog cameras, wireless just isn’t feasible.  There may be third party solutions out there, but we do not recommend them. At the minimum they would require a transcoder per each camera ($200-$400 each camera) and some kind of RF wireless solution.

This degrades image quality and affects reliability and I can’t say this enough, we do not recommend them.

Check our wireless page if you’re interested in a wireless IP system.

Q. Which system has larger channel recording devices?

A.  At the moment, IP.

Our current line of IP NVRs can go up to 32 channels on one NVR, we will soon also have our “Super NVR” line with 64 channels.  HD-SDI currently maxes out at 16 channels.

As we talked about earlier in the FAQ, the fact that h.264 compression must be done on the DVR itself means HD-SDI requires high powered processors and beefier internals.   This has limited currrent DVRs to 16 channels. We expect in the future to get 32 and larger, but for right now IP simply has it edged out.