Designing a Hybrid Video System

A guide for making the migration


Analog Cameras
Where the quality of video from an analog camera suits the purpose of the camera, there is no reason to replace the camera unless it is nearing the end of its expected life. Quality of video refers to the resolution (number of pixels vertically and horizontally), frame rate, image contrast and color; however, if a camera is intended for identification purposes (possibly in court), for example, and the quality of the image is not actually sufficient for facial identification, then the camera should be replaced with one that will fulfill its intended purpose and perhaps be redeployed elsewhere.

Analog camera signals can be brought into an IP system using video encoders that are available from a number of camera and video system manufacturers. This is often most conveniently done in the equipment rack that holds the video recording system, using rack-mounted video encoders.

Intercoms
Security can benefit from cameras at door intercoms, and the advent of IP-based intercom systems simplifies their deployment. For example, the AlphaCom Evolution products by Stentofon support hybrid intercom systems with both hard-wired intercoms and network-enabled intercoms (www.stentofon.com.au). Standard VOIP protocols encode the audio, and TCP/IP is used throughout to provide compatibility with existing routers and VLAN equipment. The intercom controllers also include a network camera port, to facilitate providing security with both “eyes and ears.”

VCRs, DVRs and NVRs
That VCRs warrant replacement needs no discussion. DVRs require some consideration. The life of hard drives in most DVRs is 4-6 years, and in most cases, DVR video storage capacity is less than desired. Thus, most DVRs are candidates for replacement; however, in some cases DVRs hold video data that must be retained from 1-5 years. For those situations, the DVR system can be retained as an independent system until no longer needed. Alternately, video management system (VMS) software can be used that integrates with the major brands of DVRs., such as Cameleon from ICx Technologies Inc. Newer DVRs that are still in good working order can even be moved out to smaller remote sites, and be monitored centrally. This can work out well for remote sites that have VCR recorders or don’t record video but simply monitor it.

A system with NVRs and analog cameras is already a hybrid system, with the analog camera signals either being accepted directly by the NVR (a hybrid NVR) or being converted to IP data using an IP video encoder. Whether to replace or keep the NVR depends on its age, its functionality and storage capacity, and the retention required for existing recorded video. The same redeployment options exist for NVRs as for newer DVRs as described in the previous paragraph.

Data center style (server-based) video storage is much more flexible than DVR and NVR units, allowing expansion as needed as the size of the video system grows or its performance requirements increase. For example, DVRs and NVRs are limited as to the total number of video frames per second that an individual unit can handle at a given video resolution. That is why the designs for most IP video systems of any size include server-based video storage using VMS software with NVR functionality.

Scalable Storage
An important aspect of future-proofing an upgraded video system is the use of scalable storage. This doesn’t simply mean expandable storage capacity. A storage system must be able to scale in two other important ways: the capacity to accept video data (how many frames-per-second, per camera) and the capacity to serve video data (which can involve both operator actions and video analytics operations). Many existing video systems can be “brought to their knees” by having several operators perform video searches at the same time. That is why it is very important to consider how video will be used operationally, before designing the video storage element of the system.