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Computer Crime / Digital Discovery / CCTV Image Recovery / Computer Forensics

Thoughts On CCTV

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Most budget CCTV systems comprise of one or more cameras that connect to a Digital Video Recorder box. Housed inside the DVR are one or more hard drives onto which the data is recorded.

The video images are often recorded in a compressed form in order to save storage space on the hard drives. Because CCTV recorders are saving data almost continuously, large amounts of storage space are needed in order to hold all the data.

To keep costs down and save on the amount of storage space required, DVRs can be programmed to hold data for a specific number of days, after which they loop back to the beginning of the recording and start to overwrite data. So, as an example, a DVR system that is set to only hold the last 7 days of data will do just that, and when it gets to day 8, this will be overwriting the data from day 1 etc etc.

The Recovery of CCTV Images

I am often asked if it is possible to recover data from CCTV systems where the hard drive’s data has been overwritten, so for example, is it possible to get data back from days 8 or further in the past? The answer, is usually no, but sometimes yes – it entirely depends how the data has been recorded on the hard drive. Samsung CCTV systems for example, record their data differently to Panasonic CCTV systems, and different approaches are used to rescue the images from both.

Written by Betty

October 16th, 2015 at 3:30 pm

Posted in Computer Crime