Digital Video Recorder (DVR) and Network Video Recorder (NVR) might be the center of your Surveillance or CCTV System operation but it needs a device to store video footage captured by the CCTV Cameras. Similar to a computer, DVR and NVR uses hard drive to store data. But CCTV hard drive is different from computer hard drive for it is designed to run 24 hours a day 7 days a week. CCTV hard drive is made to withstand constant data transfer as compared to standard computer hard drive which usually fails to last. But how do you know that you purchased the right hard drive capacity? Will it be enough to support the number of days of recording that you require? In this article, we will discuss the factors that affect the size of video data that is being stored into your CCTV hard drive.
Camera Resolution – It is a measurement describing the clarity and sharpness of the video or image captured by the CCTV camera. Higher resolutions means larger video data sizes and it will rapidly fill your hard drive space. For instance, if you have a 1080P resolution CCTV camera, you have to maximize the resolution capacity of the camera in the recording settings in critical areas. However, you can lower down the resolution of your camera in the recording settings to 720P resolution in non-critical areas to save hard drive space.
Bitrate Type – The 2 types of Bitrate Type are Variable and Constant. Variable bitrate type is usually used on critical areas where you need to maintain the quality of the video captured. This setting is good for complex scenes with lots of activities because it adjust to a higher bitrate to maintain the video quality. Thus, it takes a lot of storage space. In non critical areas, you can use constant bitrate type because it maintains the bitrate regardless of the change in scenery. This can highly contribute in saving the hard drive space.
Frame Rate – It is the measurement of smooth motion transmission in video and is usually has a unit of frame per second or FPS. The higher the frame rate means higher quality motion transmission and file size. 30 FPS or even higher is used in high speed motion such as moving cars. 15 FPS is usually used in critical areas with human movement speed. The most common is 7.5 FPS where it is used in common areas and less critical areas to save storage space.
Video Quality and Maximum Bit Rate – There are usually 3 video quality in the settings, and that is LOW, MEDIUM and HIGH. When you choose this settings, some recorders usually adjust the corresponding maximum bit rate. For instance, if you choose MEDIUM video quality for a 1080P resolution camera with 15 FPS on H264+ encoder, the equivalent bitrate for that is 1440 kbps. Where as, if you set it to HIGH with the same settings, the equivalent bitrate for that is 2880 kbps which will take more hard drive space. So in order to save hard drive space, you can set cameras on non-critical areas into LOW, common areas into MEDIUM and critical areas into HIGH video quality settings.
For a basic setup, if you have 4 CCTV cameras in the office, with 1080P resolution, configured using constant bitrate type, on 8 frames per second, and is set to medium with 1536 kbps on H.264 DVR encoder, your 1 Terabyte hard drive can support up to 14 days of continuous recording. Below are the summary of the hard drive storage capacity with basic setup:
With proper configuration, you will be able to maximize the storage space on your CCTV hard drive. Netmax Solutions can provide assistance in configuration of you DVR / NVR. Do you want us to configure your CCTV recording settings? Contact us and we will be happy to assist you.
About the author
Alfie D. is a technology solutions consultant for Netmax Solutions with over 10 years of experience working in Telecommunications Industry. He is a passionate learner who likes to discuss technology ideas with friends. He is also a front end web developer, system integrator, network administrator and likes to play the guitar.