DME Forensics Blog

DVR System Best Practices

June 30,2015 /

Technical Posts, / Forensic DVR Recovery /

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We are often asked what type of DVR system someone should purchase for their home or business and if there is a specific brand or model we recommend. The truth is, it is usually more about how you configure the system (including the cameras) than which system you buy. Sure, there are some really cheap systems out there which will limit your capabilities, but there are plenty of very expensive systems out there which (when configured incorrectly) can result in even worse video.

While we do not recommend any specific system or configuration, maximizing the capabilities of the DVR, ensuring good quality camera shots and having some basic policies can help companies avoid future problems. Configuration and setup are going to vary depending upon the needs of each end user, I have outlined some of the best practices and recommendations that we have, and that we use at our own office.

Hard Disk Size

Put as big of a hard disk in the DVR as it supports. If you want good quality and good retention, the 500GB disk that comes with most of the big box specials aren’t going to give you a lot. The size of the hard disk directly impacts not only the amount of video you retain, but also the quality. Having 30-60 days of video doesn’t help if it is really poor quality. To the same extent, having 7 days of really good video probably won’t help either if you don’t check the recorded footage regularly.

Recording Settings and Camera Quality

Garbage in, garbage out. Ensure you have quality camera shots covering what they need to cover, avoid shots that are covering the walls/ceilings. This will largely depend upon what the primary goal of the CCTV system is for. Focusing on after-hours burglary, workplace accidents or internal theft can all result in different things needing to be on camera.

Ensure the camera settings match the desired camera shot. Most DVRs will have a combination of different settings that can be used. I have outlined some of these settings below and refer to them all combined as ‘quality’:

  • Image Quality: usually means the amount of compression that is applied. The more compression, the lower the visible quality is and the less likely you will get finer details out of the video.
  • Frame Rate: is the number of frames, or images, per second that the DVR Captures. This setting will impact the fluidity of motion. Lower frame rates will appear more ‘jerky’ while higher frame rates will be more fluid. Additionally, the more frames captured, the more detail that is available. A lot of DVRs are limited in the total frame rate across all the inputs.
  • Resolution: Essentially the number of pixels captured. A higher resolution captures more pixels, as such more data. A lower resolution will capture less data, resulting in a lower level of detail.

All of these settings play into both the amount of video that you can store on the hard drive, as well as the usability of the video after an incident. Low quality, frame rate and resolution will result in a really long retention period, but the video will likely not be usable. Finding a right balance of these settings is crucial for having effective surveillance, and largely will depend on the type of business and what the goal is.

If you are concerned about work place accidents/theft/fraud, you can have high quality continuous recording settings during work hours and switch to motion or activity based recording for the off hours. Alternatively if your primary concern is burglary after hours, you could have limited daytime recording and adjust quality settings overnight.

Following on with that, I have seen some video where they had a camera set to motion record mounted in a poorly secured housing outside. In that situation every time there was a breeze or a vibration the camera moved and triggered recording. This not only will fill up your disk faster, but it makes reviewing a pain. We have seen DVRs with motion based recordings that can reach and exceed a million clips.

As an example to summarize all of this, here at our office we use a standard 8 channel DVR/Camera bundle sold at Costco. Our primary concern is burglary after hours. We set up our system to have a continuous recording during business hours at a medium quality and frame rate. This allows us to have some video for general liability reasons. After business hours, we downgrade the quality settings for some shots and then use motion based events to increase the quality. That way we continue to have full recording of our entire office overnight, but if there is an incident, the quality is boosted and we can get better shots.

Archiving/Exporting After an Incident

Don’t wait until an insurance claim is filed or a lawsuit arrives to export the video. You should have a policy to export and retain video immediately after the incident occurs.

You should export as much data as is relevant to the incident. That may mean days or weeks’ worth of video depending upon the incident, but that way they have some data if they ever need it. If there was a workplace accident, make sure they export any video that precedes the incident (how was the pallet loaded onto the rack before it fell, when did the cleaning crew mop that area, etc.).

A General Retention Policy

Regardless of whether the video is still on the DVR or it has been exported due to an incident, they should have a consistent retention policy that dictates when material gets deleted. Some companies have a general policy of 30 days for CCTV video, however video of an incident is retained until adjudicated by courts, or statute of limitations has passed. However it is set up, they should apply it consistently so when they get asked why video may or may not exist, they can explain it.

Summary

Taking all of these factors into consideration ahead of time will help you make good choices when first designing your system. This allows you to more easily scale the system to your needs. For an average home or small business, you don’t need to invest thousands of dollars to get decent CCTV coverage, but you probably shouldn’t be spending $99 either. Use the information contained here to make intelligent decisions about what components/areas to invest in to maximize results.