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Head of product & marketing, Hanwha Techwin Europe

October 9, 2018


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SD cards: Getting the most out of these unsung heroes of video surveillance

They are small and tucked away, but we should never take them for granted.

SD cards can make a significant contribution towards extracting maximum benefit from your video surveillance systems.

They come in various formats, although your decision will obviously be affected by what your cameras’ memory slots can accommodate. The good news is that many high definition IP cameras produced by manufacturers like Hanwha Techwin have slots that permit most, if not all, available SD card formats.

So why are they so important?

The migration from analogue to IP network-based video surveillance solutions has created a common scenario where recording and storing of images can be quite remote from a camera’s location.

SD cards will help keep data safe in the event of network disruption. In this respect, if you want to avoid any gaps in what may be crucial video evidence, it is recommended that before buying you should take a close look at a camera’s specifications to check if it has an auto recovery backup. This feature will ensure activity recorded on the SD card during network disruption is automatically transmitted to the remote recording device when network service is restored.

Look out for cameras with dual SD memory card slots

Edge-based applications

The massive processing power of chipsets at the heart of the latest generation of HD, open platform cameras provides the opportunity to run multiple, on-board, third-party analytics applications such as ANPR, heating mapping and people counting, in the same way apps are used on smartphones. These elevate video surveillance from just being a security system that helps you monitor and detect suspicious activity to a smart solution that delivers so much more.

Data captured by these applications can be recorded onto SD cards and remotely downloaded for analysis as and when required. Look out for cameras with dual SD memory card slots. These will provide you with greater storage capacity, as well as the option to use one SD card for edge-based applications and the other for recording images.


I suspect many in the industry have a perception that SD cards, including those capable of storing up to 256GB of data, are too limiting in terms of how much information or video they can hold.

While they are not intended to negate the need for a network video recorder (NVR), an SD card should have more than enough capacity to meet the short term demands generated by network disruption and to record analytics data, or perhaps store images captured as a result of a camera’s motion detection function being triggered.

Equally important, an SD card ‘swrite speed should be taken into consideration. The large files sizes of images captured by full HD and ultra HD 4K cameras dictates that it would be wise to specify a class 10 SD card capable of write speeds of 100Mbps. These are on offer from most well known SD card manufacturers, such as SanDisk, which 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 your video surveillance system, make sure you populate the SD card slots before the cameras are commissioned. Leave it until it’s too late and you might just miss out on recording some critical data.

Do you have some questions about SD cards? Email Uri Guterman at [email protected]

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