Almost all video security systems include some sort of recorder to store the images the cameras capture. Years ago, the universal solution was the familiar VCR. However, the introduction of digital video recorders (DVRs), which record onto hard drives instead of tape, has dramatically changed the situation.
DVRs offer so many advantages over VCRs that they have rapidly taken over as the CCTV recording solution of choice:
Ease of locating events – Instead of fast-forwarding through hours of tape, DVRs can instantly retrieve images from any specific time or date, or automatically skip to the point on a recording when something changed.
Storage quality – Like all tapes, video cassettes start deteriorating almost immediately once you record on them – and the problem gets worse every time you reuse them. DVR recordings have no degradation at all since they are stored on a hard drive. This also makes the data easier to back up.
Multitasking – While analog VCRs can either record or play, most DVRs can do both at the same time, letting you review images while still recording.
Intelligent monitoring – The DVR can be set to take one picture per second or less – just enough to create a running record. However, when it detects motion, it can automatically bump the recording speed up to full (30 frames per second), getting every detail of the activity. Software that comes packaged with intelligent monitoring DVRs can also alert you in real time via phone, email, or text message when an incident takes place so you can immediately contact authorities or your home security system provider.
Long-term recording – While security VCRs usually offer a time-lapse mode that lets them record for long periods of time, the resulting images are not a good record of events – they record only one snapshot every eight seconds. DVRs can record full motion for weeks or even months.
For most home users, DVRs are definitely the way to go.
DVRs used to be considerably more expensive than VCRs. However, DVR prices have fallen considerably over the last few years and will continue to do so. Already, low-end DVRs and high-end VCRs have similar price ranges, and most manufacturers have stopped introducing new VCR models. Despite the increased cost, we recommend video security system buyers purchase a DVR whenever possible.
Quality
As part of your preparations, decide how much quality you need out of your DVR. There is no magic number or spec here; you need to decide how “good” the recorded picture needs to be, either for your own use later or possibly to use in court.
Instant Vendor Comparison
Select the vendors that you would like to compare
Once you decide this, you'll be able to look at sample recordings on the DVRs you’re evaluating and see if they meet your standard. Vendors may be eager to throw compression settings, pixel counts, and other statistics at you, but those numbers are irrelevant if the picture doesn’t offer the detail you need.
Sizing
The size of the hard drive dictates how much you can record. On the low end, a 160-gigabyte (GB) hard drive will store about 10 to 16 days of full-motion video from one camera. Since you won’t typically be recording full motion, this is more than enough space for residential users.
You’ll also need to consider how many cameras you want to connect to the DVR. Keep your future expansion needs in mind – buying a higher-grade model to get more inputs and more storage space can save you considerable money in the future.
Other DVR specs
If you ever have to use your security images – in court or in other ways – you’ll need to export the video. This is an important consideration; some systems let you create industry-standard .avi files, which can be played on any PC. Others only allow you to export proprietary formats that can only play on the same brand player. Most DVRs do offer the option to connect a home VCR or recordable DVD player – this allows you to simply tape the digital recording onto standard media.
When shopping for the right home DVR, don’t go overboard with frame rate. Recorders that capture 3 fps to 5 fps are all you need for most home video surveillance use. While slow, it can still catch clean footage without impacting picture resolution.
Make sure the DVR offers 640x480 recording size, not viewing size. The North American standard for full screen recording is 640x480; any less and you may not be able to make out facial features or other details that can help authorities capture intruders.
