4 Reasons Edge-Based Recording Is Expanding

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.