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Time Lapse, VCR's, DVR's, NVR's ... | ||||||||||||||||||||||||||||||
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Now many people will argue that leaving a DVR to continuously record without the need to change tapes every day is a huge advantage, and on that point alone Doktor Jon would have to absolutely agree 100%. But ideally, we need to be in a situation where a video machine can be left to record at 400 lines or more resolution, for perhaps 31 days, with an image refresh rate of lets say for arguments sake twelve frames per second. Now if you are sitting down, brace yourself! Historically, with some of the more common compression techniques, simply to achieve this level of video recorder performance, you may actually need around ...1850 GB of hard disc space!! If however, you were recording at the same rate as an analogue 24 Hour Time Lapse machine, you could of course simply reduce the HDD's available capacity down to around 685GB (use of a more 'lossy' compression would significantly reduce the storage required, but that in itself creates further issues in terms of in terms of forensic surveillance after an event). To put it in context, that would provide the same functioning as an S-VHS machine (with some very useful additional features) and you wouldn’t have to change the tape every day! Apart from the additional purchase price for cassette tapes or digital media, it would still represent a cost ratio of perhaps 20 : 1 in favour of analogue S-VHS over a Digital DVR in some situations. One particular function of a DVR which has so far not been mentioned, is certainly worthy of consideration for a number of reasons. Many current DVR recorders will also offer the user an option of remotely accessing and controlling every aspect of their operation, using a PC loaded with appropriate software. Additional features, like 'motion detection' and 'inaction detection' (along with the start of video analytics being incorporated into some higher end models) can provide enormous benefits in key situations. Whilst even some 'entry level' DVR's are increasingly being bundled with many features not available to analogue tape based machines, 'add ons' must not be allowed to detract from a units core requirements, which are build and record quality, coupled with guaranteed reliability. Like any available CCTV technology, Doktor Jon believes that Digital equipment can offer enormous advantages in most situations, but unfortunately, most end users do not understand even the basics of what it is they are buying. In fact, one could say that simplistically, customers are buying in to a magic bullet, a “Digital” dream where everything is better, simply because it has the ‘D’ word stamped on the front. The bottom line is that until DVR technology consistantly surpass the performance of existing ‘proven’ technology, and at an equivalent cost, and without any obvious operational disadvantages, then most people would be advised to do their homework very carefully, and then make an informed choice based on requirements. | ||||||||||||||||||||||||||||||
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