Geutebruck CCTV systems can now retain high quality video for long periods using only a fraction of the normal storage capacity.  Their new ‘fading long term memory' (FLTM) option reflects the fact that, where different kinds of event are discovered, handled and investigated in different timescales; there is no real need to continue storing video at the full 25 fps for a month or more, if lower frame rates suffice after the first few days.  FLTM software therefore enables you to progressively reduce the frame rate of your stored footage as time goes by, in accordance with your assessment of residual risks.

Let's imagine your system has to deal with robbery, vandalism and fraud, and you have to retain a video record for 30 days.  Robberies are discovered and pursued promptly, so within three days all relevant 25 fps footage has been reviewed and backed up.  Vandalism is dealt with in a week and 6-7 fps footage is adequate.  The timescale for fraud is longer but 1 fps provides the necessary evidential detail. 

Normally, for high quality real-rime video @ 4Mbit/s, storage per camera would be about 43.2 GB per day, or 1.3 TB for 30 days.  But with FLTM you only need:

3 days @ 25 fps ≈ 130 GB

+ 4 days @ 6.25 fps ≈ 90 GB (differential compression reduces data by about 50%)

+ 23 days @ 1 fps (I-frames only) ≈ 70 GB 

A total of only 290 GB per camera - which enables you to make significant hardware savings without any loss of benefit, utility or security.