Why do CCTV images are different from other common cameras?
June 29, 2009 by Surveillance Tips and Advice
Filed under GPS Tracking, CCTV, DVR & Private Investigation
Can you answer Fraz’s question about Surveillance?:
I don’t know how to explain my question; but everybody knows that CCTV footage doesn’t appear smoothly on screen but its always in broken segments; broken into split seconds. Why a CCTV footage not clear and smooth like other common camera videos.
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I don’t know how to explain my question; but everybody knows that CCTV footage doesn’t appear smoothly on screen but its always in broken segments; broken into split seconds. Why a CCTV footage not clear and smooth like other common camera videos.
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Surveillance Feedback: Right depending what system does what ideas.
you used to have for sale time lapse video recorders that you connect to a multiplexer, these units took your cameras and made a series of still photos to be recorded on tape. when you have 16 cameras recording on a 24 hour tape you would get a picture about 40miliseconds of each camera, thus by the time it comes back to camera one time has elapsed by a few seconds. this also hopes that the equipment are in good order but when tapes are old and the recorder get old the data and pictures are not so good so only a few frames in every few seconds. this is still used but is really “old hat” now (some courts throw it out for being old and of unusable quality)
the later equipment is digital recording down to hard drive, the stuff now can produce pictures thats DVD quality but usually loose on frames per second, but still 6 frames a second well be better that 1 frame every 2 seconds. this resolution is named D1where the older digital recorders only used CIF which is VCD/SVCD quality and really old used QCIF which is CIF divided by 4.
todays color cameras are better electronics but many that was installed years ago are in need of replacement as they die around 5 years and they get to have problems, apart from that they was not of high quality comparing them to today.
so to recap if your using a multiplexer you separate your cameras on to one tape (not like your normal video camera, one camera one tape) this is why they jerk
EDIT: also im not saying that modern units only record at 6 frames a second some will record real time (25FPS) but usually not in the D1 resolution. there is also compression too, some use mjpeg, mpeg4 and the later use H.264 which is the codec for HD TV. the more you pay the better you get but installers usually go for better quality recording although some of the time rather than faster recording of less quality. you don’t really need to record in real time usually 8 to 12 frames a second is all you need