When looking for a DVR, there are more options out there than models of TVs. That is why I am going to discuss certain topics that are important for you to know and understand before buying your DVR. How do I decipher some of the terminology? Why should I spend my money on one over another? What are the biggest differences in units? What brands are the best? These are just a few of the questions that you may come up with when trying to purchase a security system.
How often have you been watching the news and have seen footage from an incident shown, and you look at the screen scratching your head wondering what you are looking at? There are a couple of factors that come into play with the footage that you are seeing. There is the quality of the camera that was used with the system. The quality of the cabling that was ran from the DVR to the camera. And what I feel to be one of the most important factors is the DVR itself. When it comes to a quality surveillance system the heart of the system is the DVR, the backbone of the system is the cabling and power supply, and the cameras are the eyes. If your main component is weak the rest of the system will suffer.
One of the biggest things you need to worry about with regards to a DVR is the recording resolution. A lot of systems out there will tell you that you are getting a high resolution system. This is normally because they don’t want you to research the system any more and generally said when they are giving you what they consider to be high resolution cameras. They do not want to talk about the fact that the images the DVR will be recording are subpar. It may look decent when you are watching the screen live, but when you actually go and try to see something in the recorded footage it will not look like what you were just watching live. This is because of the recorded image resolution. When it comes to the recorded image there are 2 factors resolution and frames per second (fps). The resolution is the biggest of these 2 factors. There are several different resolution that a DVR can have the ability to record at. They are QCIF, CIF, 2CIF, HD1, 4CIF, D1, or 960H. The quality of the resolution increases from left to right with QCIF being the lowest and 960H being the highest resolution that a DVR can record at. Most DVRs on the market can record at the lower end of the spectrum, but not all of them can record in the 4CIF/D1 spectrum and even fewer can record in the 960H.
CIF is short for Common Intermediate Format, which is a common video format. Its resolution is 352×240, which means that those 700tvl cameras that you spent good money on are wasted. This is because you are only getting approximately a third of the potential tvl being recorded. The rest of the tvl’s are being discarded. This format was very useful when technology could only support it, but we are well above that now. This type of a format is relevant for remote viewing so that you get a more ‘live’ picture and are generally limited to the bandwidth of the ISP provider. Viewing your system remotely in CIF is a better solution than having network drag or high latency with your ‘live’ view.
Quarter Common Intermediate Format or QCIF has a resolution of 176×120. Now if your DVR is only recording in this, throw it away and step into this century. This format will take your high resolution 700tvl cameras and only give you about a fifth of their ability. The only reason this format should currently be used is for mobile phone viewing. It allows for the images to be transmitted at a greater rate over a cellular network with less latency. You typically are viewing these images on a much smaller screen, so the loss of resolution isn’t as apparent as viewing it on a normal monitor.
Twice Common Intermediate Format or 2CIF has a resolution of 704×240. This resolution is starting to give you more use out of your 700tvl cameras. You are still getting a smaller image horizontally, but a more natural vertical resolution. So your 700tvl camera will give you all of the detail that is available to you based on the vertical resolution. If you are recording in this format it will save you space on your recorder, but you are still falling short in the horizontal resolution of the image. This can sometimes be referred to as Half D1 or HD1. They can also have a resolution of 352×480 which in today’s monitor world does not make sense. It made more sense when you were dealing with square monitors.
The best choice for today’s high resolution cameras is Four Common Intermediate Format or 4CIF which has a resolution of 704×480. This is commonly referred to as D1 resolution as well. This comes in very useful for capturing all of the details that are possible in an analog CCTV camera. A 625tvl camera will be the maximum tvl’s that will be needed to maximize your images with this recording format. That being said, more is often better. This is because of other features and components that are often used with higher end cameras. That will be discussed in a later article.
The absolute highest rate of resolution that an analog CCTV system can record at is referred to as 960h which has a resolution of 960×480. What this allows for is an even larger image for more detail in the image. This resolution requires 2 things to properly be utilized, a DVR that can handle this resolution as well as cameras that can support it. Your cameras need to be high resolution with good sony digital signal processors (DSP) that are designed for 960h and a federal series DVR. The Tech Pro Federal Series DVR is an amazing unit for the absolute best performing DVR on the market. This setup is amazing for upgrading a system that has all coaxial cable in place, but you want to get HD without re-wiring your whole place.
Frames per second or FPS is another thing to consider when looking for a DVR that best suits your needs. Most DVRs on the market, if they can record at D1 resolution, do so at 7fps. This is generally suitable for the general consumer market, but if you are needing to see in realtime you need a unit that will record at 30fps. This is very useful when reviewing the footage because you have more frames in a small period for you to better see what occurred. At 7fps, an object can be in one place and then in the next sequence a little ways away. This is why a lot of DVR manufacturers will sacrifice the D1 for recording in CIF. Me personally, I would rather have a greater image quality and loose a little on the fps than have real time and a poor image. The better the image quality to start with when degrading the picture the better that degraded image will be. When you start off with a poor image and then have to degrade the image to see what you are looking at, you lose.
My DVR of choice is the Ultimate Mini Series, it has great features in a compact package. You get D1 resolution at 30fps on all channels, it is able to accomplish this with its dual core processor. You also have some pretty cool features like audio inputs, alarm outputs, video matrix, and an HDMI video out display to name a few. The DVR is about the same size as a Bluray player, so it can fit in almost anywhere. There are a lot of different units on the market that may suit your needs. What you want to do is decide on what the most important features are for you and then proceed with building your system. Just remember that all things are not created equal and you may be better off saving a little money to get you a unit with features that will help you when you need them rather than just getting anything. The last thing that you want to do is find out that you wasted your money when you really need the footage to help you capture the perpetrator. Contact us today for more information.