RhinoCo Technology - Calculating Video Surveillance Hard Drive Storage Requirements

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Calculating Video Surveillance Hard Drive Storage Requirements

Published 2017-04-01

Determining how much hard drive storage is required for a particular installation can be a complicated task.

This article explains some of the technical details about how video is stored. If you're in a hurry you can jump straight in and download our Disk Calculator Tool.

How long do you need to record?

When assessing hard drive storage, the first issue is to determine whether there is a minimum amount of recording time required.

This could be a time frame imposed by the end user, such as "I go overseas for 2 weeks at a time, I want all the footage available when I come home". In a situation like this, it would be wise to provision at least 3 weeks of recording storage. This gives the end user a few days to review the footage upon their return, if an event has occured.

Alternatively, the end user may be bound legislation. For example, in Queensland, licensed venues must store recordings for a minimum of 28 days. It is advisable that the installer and end user are aware of legislative requirements.

A professional security installer will usually take the time to discuss their clients needs to determine the amount of time recordings need to be kept.

How much storage do you need to meet the recording time line?

In general, calculating the amount of hard drive storage required is as simple as:

Number of cameras × Number of days recording × Storage used by each camera per day

The amount of storage used by camera per day is driven solely by the bitrate used. When configuring the bitrate in your camera or recorder, you will usually see it referred to as kilobits per second or kbps.

The higher the kilobits per second, the more hard drive space the recorder will use to store a single second of video. Using a lower bitrate will reduce the quality of the recorded video.

Working out the best bitrate setting to use can take some time and adjustment. A camera that encounters a large amount of motion activity or has a very complex scene, will require a higher bitrate than one looking a static view.

Another factor to consider is the frames per second that are recorded. Recording one frame per second at specific bitrate (say 2,000kbps), will result in a higher quality recording than the same bitrate at ten frames per second.

If you are interested in learning more about bitrates, we recommend the What is Bit Rate? video on Youtube.

Recorder Bitrate Configuration

Disk Calculator Tool

Example: The Disk Calculator Tool, calculating the disk requirements of a 16 channel setup.

To assist with calculating your requirements, we have a Disk Calculator Tool available for download.

The Disk Requirement tool estimates the required HDD size needed to record on the recorder over a set number of days, while the Recording Day tool estimates the amount of time the recorder can record for, based on the bit rate, video channels and HDD space of the system.

Click the Add Streaming button at the top left to add a new camera.
Enter how many channels will be used.

Enter the bit rate of the camera. There are two methods to doing this:
a. Manually - Enter the bit rate in the text box on the right. Refer to the table below for recommended bit rates for various resolutions.(Recommended)

Compression	Resolution	Frame Rate	Recommended Bit Rate
H.264	1.3MP	15	2048
H.264	2MP	15	4096
H.264	4MP	15	6144
H.264	8MP	15	8192
H.264	12MP	10	8192
H.265	2MP	15	2048
H.265	4MP	15	4096
H.265	8MP	15	6144

b. Automatically - Enter the compression, resolution and frame rate of the camera using the drop down menus. This will estimate the bit rate of the camera and automatically enter it into the text box on the right.

Repeat steps 1-3 for every additional camera with a different bit rate.
To calculate disk requirement, click the Disk Requirement tab. Enter the amount of recording days desired for the recorder and click the button on the right.
To calculate recording time, click the Recording day tab. Enter the storage capacity of the recording and click the button on the right.