SD Cards – The unsung heroes of video surveillance

Uri Guterman, Head of Product & Marketing for Hanwha Techwin Europe, explains the importance of SD cards and provides some useful tips on what to look out for when buying them.
Although they are small and often tucked away, we should never take them for granted. SD cards can make a significant contribution towards end-users achieving maximum benefit from their video surveillance systems.
They come in various formats for you to choose from, although your decision will largely depend on your camera’s memory slots. The positive news is that many of the high definition IP cameras produced by manufacturers, such as Hanwha Techwin, have slots which allow customers to use all the available SD card formats.
Why are they important?
The migration from analogue to IP network-based video surveillance solutions has created a common scenario where the recording and storing of images can be remote from a camera’s location.
SD cards will help keep data safe in the event of a network disruption. For example, if you want to look after crucial video evidence, it is important to research a camera’s specifications to check it has an Auto Recovery Backup, before purchasing.
This feature will ensure activity recorded on the SD card during network disruption is automatically transmitted to the remote recording device when the network service is restored.
Edge-based Applications
The substantial processing power of the chipsets at the heart of the latest generation of high definition open platform cameras provides the opportunity to run multiple on-board third-part analytics applications such as ANPR, heat-mapping and people-counting, like smartphone apps.
Rather than a simple security system that monitors activity, video surveillance is enhanced, delivering a smart solution which is capable of much more.
The data captured by these applications can be recorded onto SD cards and downloaded remotely for analysis when required. When researching, look out for cameras with dual SD memory card slots, as these will allow you greater storage capacity, with the option to use one SD card for edge-based applications and the other for recording images.
Capacity
There’s often a perception that SD cards, including those which are capable of storing 256GB of data, are too limiting in terms of how much information it can hold.
Whilst they are not intended to negate the need for a Network Video Recorder (NVR), an SD card should have more than enough capacity to store the short-term demands caused by network disruption. They will also be capable of recording analytics data or storing images which have been captured by triggering a camera’s motion detection function.
It’s also important to consider the write speed of your SD card. Lage file sizes of images captured by Full HD and ultra-high definition 4K cameras dictates that it would be wise to specify a Class 10 SD card that is capable of 100Mbps write speeds.
These are on offer from most of the well-known SD card manufacturers, such as SanDisk, who will also provide you with peace of mind in terms of quality and reliability.
The Options
SD – Up to 2GB
SDHC – 4GB to 32GB
SDXC – 32GB to 2TB
Whatever you hope to achieve from a video surveillance system, make sure you populate the SD card slots before the cameras are commissioned. Leaving it late could make you miss out on recording critical data.

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