CCTV footage

well, i managed to find a langthy report about this system from a group called Urban Eye:

http://www.urbaneye.net/results/results.htm http://www.urbaneye.net/results/ue_wp10.pdf 

inside i found that the footages are recodred on tapes (?!?) in 3 seconds time laps format, and each tape is kept for 31 days, and recoreded over and over for 12 times.

but it sounds a bit outdates to still use video tapes, not to mention expensive and troublesum.

a modern system, probably would use digital cameras and digital storage based on either Hard drive arrays or computer Tapes (which save multiple copies at a time for backups) and also use high end data compression to save space. but i was unable to find something about this in regard to london system.

there is also consideration about something called Data Protection Act that deals about saving and transfering this footages to others:

http://www.ico.gov.uk/eventual.aspx?id=5739 

hope someone will able to digg out more info about this.

I can't answer for sure but when I plan city surviellance system for big cities I limit the system to keep information for 1 month (for an ordinary client) or 3 months (for a reach client). If there was no event, than after the time period the recording is deleted by another recording.

The format today is usually digital video format. Nobody uses tapes anymore. It is recorded on hard drives. You can use the ordinary AVI type of files or more specific codecs with better compression rate (to save space without losing information).

Omer