Doktor Jon Posted November 20, 2006 Share Posted November 20, 2006 Triggered recording is a simple solution to the age old problem of cramming more time coverage onto a fixed size record medium. Whether technically it works 100% of the time or not, I would still agree that a slow rate continuous record system is far preferable, as that would effectively reduce any potential risk of the recordings being legally challenged, on the basis that possibly vital evidential material was missed. Link to comment Share on other sites More sharing options...
james.wilson Posted November 20, 2006 Share Posted November 20, 2006 so to summerise, where hard disks are no object as high frame rate as your disks will take where not low frame rate when the scene is inactive, and high framerate when there is activity in the scene Doktor, what do you class as realistic framerates for the above situations? James securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
Rich Posted November 21, 2006 Share Posted November 21, 2006 16 frames per second is usually requested as a minimum. Link to comment Share on other sites More sharing options...
cutwitt Posted November 21, 2006 Author Share Posted November 21, 2006 Thanks all round folks. All makes good sense. Advice squares nicely with what I have been told by law enforcement. Turns out it may be academic for my current DVR as I have just discovered that I can capture a series of nice sharp 70K jpegs on motion events and also record D1 realtime simultaneously. Jpegs, as expected, are a bit sharper than stills taken from the H.264 video. In terms of evidence I guess its capturing as much data as doing it the other way with a continuous stream of jpegs. Horses for courses perhaps. Not crashed yet, but it's early days! Fingers crossed. Link to comment Share on other sites More sharing options...
james.wilson Posted November 21, 2006 Share Posted November 21, 2006 16 frames per second is usually requested as a minimum. 16 fps per input? or 16 fps accross them all? securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
Rich Posted November 21, 2006 Share Posted November 21, 2006 16 fps per input? or 16 fps accross them all? 16 Fps per channel minimum, constant or motion record. A combination of both would best be 1 FPS per channel idle then 16fps per channel minimum per alarm event. The 1 frame per camera every second would serve the purpose that the machine is working, and prove that there were no missed motion triggered events. I am not sure if this has changed into an actual requirement but I have heard of CCTV footage being dismissed on the basis that there was no way to prove that there wasn't any activity for the DVR to record previous to the triggered recordings, hence not knowing if the DVR was functioning properly without fault. Although saying that my understanding is that the "pre record" function was to ensure that this wasn't the case. Link to comment Share on other sites More sharing options...
james.wilson Posted November 21, 2006 Share Posted November 21, 2006 16 fps per input thats high i think. thats virtually real time. securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
Rich Posted November 21, 2006 Share Posted November 21, 2006 16 fps per input thats high i think. thats virtually real time. I believe police specify 16fps and it comes from the document that Lee Tracey had created which I think is the same Dave Phelps is refering to (don't quote me on that though) I think it is based on the human eye not being able to distinguise the individual frames at about 15fps so for general CCTV use for almost real time video as we percieve it, is 16 frames per second of video and seems to be a popular "desired" frame rate. 16 is just the figure that has been commited to memory from wherever I have read it from, in situations where the hand is quicker than the eye (casinos) then they generally require a higher frame rate. Link to comment Share on other sites More sharing options...
james.wilson Posted November 21, 2006 Share Posted November 21, 2006 i can see casinos and maybe cameras on tills etc wanting high framerate maybe even retail public areas but general cctv, i think its a waste of hd space. Hopefully dave will send me this document?!?!?! securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
cutwitt Posted November 21, 2006 Author Share Posted November 21, 2006 i can see casinos and maybe cameras on tills etc wanting high framerate maybe even retail public areas but general cctv, i think its a waste of hd space. Hopefully dave will send me this document?!?!?! Would like to see that too. Maybe someone could post up the basics. Link to comment Share on other sites More sharing options...
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