A monumental increase in SD card storage capacity is perhaps the most significant reason why edge-based recording is finding favour in security installations across the UK this year.
You only have to look how far we’ve come in the last few years in this area. Original SD cards could only provide 2GB of storage just 10 years ago. High Capacity SD cards (SDHC), offering up to 32GB, reached the market in numbers some five years ago.
This development prompted an explosion of IP surveillance camera launches with in-built SD card slots designed for edge-based recording. Then, new SDXC cards (eXtended Capacity SD Cards) offering 2TB of storage capacity began to reach the market, and 128 GB SDHCs and SDXCs are available today in larger and larger numbers with prices falling fast. This is a game-changer for edge-based recording because it makes storing high frame rate HD video images increasingly easy and inexpensive.
This explains why almost every new camera model launched this year comes with an in-built SD card slot. So, why has edge-based recording gained ground so rapidly in the last few years?
Click here to view Figure 1.
Expansion of SD card capacity
The most obvious reason for edge-based recording gaining popularity is the wider availability and lower pricing of higher capacity SD cards, with 32GB being the breakthrough in terms of local storage capacity in our view.
Axis Communications produced this storage capacity table based on the use of 32GB SD cards:
|
32 GB SD/SDHC card*
(days)
|
Storage/day*
(GB)
|
Frame rate
(fps)
|
Camera
resolution
|
|
45
|
0.7
|
15
|
VGA
|
|
27
|
1.2
|
30
|
VGA
|
|
19
|
1.7
|
10
|
HDTV 720p
|
|
9
|
3.6
|
30
|
HDTV 720p
|
|
* Numbers are calculated using AXIS Design Tool, based on 30% H.264 compression, 20% motion detection and medium scene activity.
|
Even with recording at HD 720p resolution at 30 frames per second, it is possible to store up to nine days of images assuming default 30 percent H.264 compression and other standard parameters including use of motion detection. If you quadruple the SD card’s capacity to 128GB — suddenly it becomes possible to record a month’s worth of HD images “at the edge,” potentially only backing up into a central storage archive facility periodically, or on analytics triggered events or known security incidents.
For installations where network bandwidth is variable or non-existent
The trend to higher resolution video means increased demand for bandwidth, which is not always there. Edge-based recording offers a distinct advantage in such low bandwidth scenarios. CCTV users can view the live streaming images from cameras in low resolution, using little bandwidth, while recording HD quality CCTV footage locally on the cameras. These high quality images can be easily retrieved from the SD card following incidents that demand further investigation.
For local recording backup and analytics capability
Increasingly, it is possible to do more sophisticated analytics processing in the camera. Leading manufacturers fit motion detection, audio detection, even ANPR, tamper alarm, auto tracking, and tripwire analytics capabilities in many cameras today. At IFSEC International, we saw some high-end Mobotix cameras with very sophisticated
“learning the scene” type analytics, which help differentiate genuine movement from background movement associated with wind, water, rain, or snow for example. Reliable facial recognition will soon be possible in-camera also.
It’s possible that cameras can be programmed to record to a SD card at different frame rates and resolutions depending on the type of alert, time of day, and perceived threat level, and if the network connection is lost at that time.
Fail-over recording, as it is sometimes called, means that images can be temporarily stored in the camera in case of network failure. This adds resilience to mission-critical security systems. Central video management systems are often configured in these scenarios to retrieve and merge local video recordings seamlessly so that complete video sequence is restored in order of the actual events. Genetec Omnicast Archiver recording management software can do this — automatically retrieving and permanently archiving the edge-captured video from the camera to fill central recording gaps sustained in a period of network outage.
For distributed organizations where low maintenance local recording is desirable
Increasingly, restaurants, pubs, and other retailers are part of larger and larger chains. In this scenario, centralized security management may not be practical or even desirable. In one increasingly popular scenario, network cameras fitted with SD cards permanently store video data at local stores. The manager of a store might check on video recordings or view live images, perhaps following pre-configured alerts, via his PC or mobile device if he is away from the outlet.
Installer view
Our experience bears out a great deal of the above drivers. Many of the construction sites that we are asked to install cameras at offer no bandwidth connections, and sometimes no power source at outset. For one site, we recently had to deploy solar and wind turbine-powered surveillance systems. There are many remote locations for surveillance, which lend themselves to local recording with periodic centralization of recordings for backup and archiving purposes — either for post-event analysis or simply to add resilience.
The fact that Video Management Systems (VMS) are being redesigned for easier deployment and integration also makes it possible for camera manufacturers to embed VMS functionality into cameras themselves. If there is one underlying trend it is to put more and more functionality at the edge — not just the video recordings, but analytics processing and video management tasks.
Our view is that with the rapid growth of edge-recording and increasing availability of more robust video-surveillance-as-a-service (VSaaS), the physical centralization of video storage and management (with its associated banks of servers loaded with enterprise versions of VMS software on them sitting in the back rooms of large Centralised Monitoring Units) is fast becoming just one of several configuration options, even for the largest surveillance system owners.
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It is fun to think about how much storage capability these SD cards have now and compare it to what it would have taken 5, 10 or 15 years ago. The really amazing part of it is that it allows edge recording at such a level of detail that the image quality is really astounding. And on a large card you can store weeks worth of data, the only draw back is that someone who is knowledgeable about the device could tamper with the card at the source but I would guess those individuals are few and far between.
I’m definitely of the opinion that SD storage is most suitable either as an extra bit of storage for resilience or for small installations where there is less budget for a dedicated storage solution.
I’m also in agreement that edge based storage is best as a backup or secondary storage in many applications, but that’s as a rule of thumb. Often the camera takes the most abuse, and I’m not crazy about SD card reliability to begin with. We’re going to see the same read/write issues that we’ve seen on solid state drives for computers, perhaps more so as SD cards were never designed for continuous overwriting. Also, steal the camera and you steal the storage. That being said, there are scenarious, as the author points out, where edge based recording just makes sense.… Read more »
@Robert Brown: Yes indeed and when you consider the security aspects, its much more ahead than the others. Also cost-wise its reasonable.
A simple way to overcome any concerns re. SD card interference is to tamper the camera housing theyeby giving an instant indication that the system may be under attack.
However, quite how well protected the SD cards are against high levels of external magnetic interference may be the subject for another post.
Just like the explosion of mobile and smart phones, edge devices simply fill a need and provide value. But, just as with all edge devices, the nicer they become the more valuable a target they become. As an InfoSec Pen Tester, my business case for Camera Sneak-Ups tests grows. First, I get to capture the image history of my sneak-up; to learn how to do so better. Second, free memory chips would itself be an attactive target. Last, if my Pen Test goal is to enter the edge and benignly prove that data processing flows can be unfavorably altered,… Read more »
Great point, Robert: another useful weapon in the armoury!
Ah another great point. Would it be possible to rotect from magnetic interference? (maybe, as you say, for another day…)
That would vary wouldn’t it, but yours was a rhetorical question, I think.
A growth in tamper detection would be a logical supplementary conclusion of edge storage. Perhaps also hidden SD card slots and maybe even false SD slots. The problem with that being it doesn’t take a genius to Google where these false slots are.
Symetric Digital Warfare: Identify, Immobilize, Isolate and Remove. The greate advantage of cameras is in the Identify phase. The great problem is clarity and retention. I think the increased memory actually helps the case of a Camera as a deterant. If I knew, that I could not simply enter the building, mondify financial software and leave largely undetected — if I did not alert the defenders. Then, the fraudware installation wait dormant until the retention period of diginal images expired. If camera retention expired before detection, there would be less evidence to Identify the attacker. This attack profile is harmed… Read more »
@ Robert Grossman, Steal the camera and you steal the storage, which effectively means that you have to employ someone to keep an eye on the camera itself. But keeping other considerations in view like budgetary constraints, power and bandwidth issues at remote sites, edge based recording might be the best option of not the only one.
I am really amazed by features mentioned in the post especially like learning the scene, differentiating between back ground movement and actual movement and different frame rates and resolutions depending upon different indicators. It seems we are marching toward some sort of “Smart Cameras”. Are we? Besides, ability to capture and store temporarily during network outages and fill recording gaps afterwards, is kind of “Disaster Management”.
Right, so in your scenario a person hides a dormant malicious attack and waits until surveillance images will have been written over, is that right? I’m not sure the average criminal has such patience, only the most skilled. But then those people are the ones with the potential to get the bigger scores, so indeed security wins.
Funnily enough ‘smart cameras’ is the one phrase I haven’t heard being banded about the industry yet, even though you could probably use that term quite correctly. I suppose ‘smart cameras’ is a bit of a consumery phrase and security technology remains largely not a consumer market. The ‘smart’ technology is all over the place: in the camera maybe, the VMS probably
I absolutely agree. It’s an exciting concept and it brings another aspect to system design and configuration that will benefit many. My only caution is the old axiom “When the only tool you have is a hammer, pretty soon everything looks like a nail”.