by Germán Alexis Cortés
In the last edition the author began to answer if megapixel cameras are necessary by explaining what they are and their characteristics. On this occasion, other elements that complement this technology will be presented.
Transmission medium
The vast majority of megapixel cameras, which are on the market, are fully digital, that is, their output is IP. Therefore I must make sure that the bandwidth of the network that this video carries is sufficient for the large amount of continuous information that is sent.
The quality and category of the data cable influences a lot. I always recommend for this case to use the highest possible category (6A or 7) and the use of connectors, patchpanel, patchcord and other passive elements of the network, of the best possible quality. Ensuring that communication over this end-to-end cable is flawless and has the best ratings in the certification process is a guarantee of a high-resolution video signal in good condition.
If your budget allows, bring fiber optics to every unit, it may seem exaggerated today, but in a few years you will have the best and only capable medium to transmit high-resolution video.
Bandwidth
The required bandwidth grows considerably. For example for a signal of 2 Mp, at 30 FPS, I require almost 20 Mbps, and if I have 10 cameras I must already have 200 Mbps effective free, which leads me to work with LAN networks of minimum 1 Gbps. At the WAN level I must be aware that I must lower the quality or pay an astronomical sum for a channel of this magnitude dedicated to video. However, let's remember that I don't always need the maximum resolution at the maximum speed, except in high-risk cases.
But make no mistake, for now megapixel cameras are not for transmitting at the best speeds and resolutions through traditional data channels. As we realize in training courses, it is better to record locally at excellent resolution and speed; and stream a different video stream at a speed and resolution appropriate to the bandwidth of the medium you have.
Additionally, some Megapixel cameras can generate video signals in traditional VGA resolution occupying a low bandwidth and automatically increase to the maximum resolution, when an image change is detected or an external event arises. This really allows a considerable saving of both bandwidth and hard drive.
Video recorder – NVR
The VCR (NVR) must have the ability to handle these high-resolution native video signals. In this case, many traditional software packages on the market for video management do NOT work because they convert signals to CIF, VGA or D1 resolutions. Losing a lot of information. Even if you watch the video of good quality, you will only realize that it is high resolution if you can see it in native size (it will surely not fit on the screen) or if it allows you to do many levels of digital zoom without losing quality.
Keep in mind that your NVR processor should be able to handle much more information than working with analog-resolution IP cameras. I recommend that your video recording server has a lot of RAM and that your hard drives have high data transfer capacity (look at the write speed).
Nowadays with the issue of storage virtualization, you will be able to use databases in NAS configuration and even SAN, however remember that in high resolution a data flow is handled 13 to 60 times larger than normal.
Networking
Networking equipment (switches, routers, among others) must ensure that they will be able to handle all the information from all the cameras simultaneously. A wrong choice of the entire active part of communications will be fatal to the performance of the high-resolution video network.
Do not forget that in critical situations you should record at the highest possible speed, in the best resolution allowed. This continues to be true in high-resolution video.
Verify that your VCR simultaneously records on all channels at the native resolution of the cameras at least at the speed (FPS) that the megapixel camera handles at most.
Hard disk
And what about the capacity of the hard drive? Yes, you will indeed need much more hard drive. The formulas for hard disk calculation are still applied, the only thing that changes is that the average size of a frame under standard conditions for a 3 Mp camera, can be approximately 80KBytes; that is, 20 times greater than the typical compression for a CIF format. Even so, it is noticeable that video compression engines are becoming more efficient, because a CIF signal is 27 times lower than an HDTV.
To give an idea, a 500 GB hard drive, I can store only 2.5 days of continuous video at 30 FPS of a camera with a resolution close to 3 Mp. Then very soon the capacity of hard drives will be given in Tera Bytes or Peta Bytes. And we're still getting started.
Monitors
The monitors where I must observe these cameras must also be of high resolution, to get the best out of the whole system. Prefer high-tech (LCD, Plasma, DLP, LED, among others) with high resolution. Do not fall below the resolution that today is known as HDTV (1920 x 1080). This will allow you to see in the best way cameras up to 2 Mp.
Needless to say, we should not use the monitors of a traditional PC as CCTV monitors. Much less using high-resolution cameras because there we lose the resolution that we gain in the rest of the devices.
The video walls (videowall), built with DLP type rear-projection modules or similar, are an excellent option to visualize megapixel cameras, since you can see the image at full resolution segmented between many high-resolution monitors.
Other ingredients
The rest of traditional CCTV equipment, protections and tips to achieve an adequate video signal, are still maintained. Therefore, all that we have added is a component that will significantly improve the surveillance system.
The new trend to increase the resolution of video (and photographic) cameras will continue continuously, perhaps until we reach the resolution of the human eye in all components. I must say that it will be many years before this. So we must be prepared for a series of periodic updates that allow us to improve sharpness in the scene, gaining a lot of information.
Surely at first the costs of all accessories and the same camera can be seen as very onerous, however as always happens, the market has already seen its innumerable advantages, it will begin to consume and this will cause prices to fall considerably. But don't wait for this to happen, jump in now to have at least a few high-resolution drives. I assure you that you will not regret it.
IP cameras are here to stay and if you needed strong and strong arguments, high resolution is one of them. In ideal conditions of resolution, transmitting over channels with excellent bandwidth, storing on high-capacity hard drives and observing on appropriate monitors; I must say for now, that the experience of having a Megapixel IP camera system is unbeatable.
*If you wish you can write to the author at the email [email protected]
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