DVR’s
Conventionally, video surveillance and security camera monitoring has been recorded to VCRs (video cassette recorders). Old VCR systems required intensive follow-up and maintenance because of the need to change, replace and recycle VHS tapes; furthermore, overwriting cassette recorders over and over again deteriorated picture quality and resolution. Digital video recorders (DVRs) replaced VCRs, the storage media were no longer dependent on intense labor intervention or tape quality. Video images are stored digitally on internal hard drive storage. Some of the main advantages of digital video recorders are: extremely better image quality, ease of use, advanced search capabilities searching a video with specific date and time, simultaneous record and playback, no image degradation, improved video compression and storage, remote internet monitoring, recording, maintaining and more
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Digital Video Recorders come in various channel camera inputs. starting with 1 channel DVR and can go up to 64 channels. The DVR has a built in multiplexer which will allow you to view all of the camera channels at one time on one screen. and all the video is saved to the hard drive separately. Therefore, the conventional way of connecting a switch, quad, or multiplexer is not required with a DVR.
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A great range of multi-channel DVR cards from GeoVision (and other manufacturers) Also Standalone DVRs
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When purchasing a DVR there are a number things to look for:
?Frame Rate is important, as the higher the Frame Rate, the higher the quality of recording and the more Real Time your cctv recording will be. Real Time Recording for 1 camera is 30 Frames Per Second. In order to capture 16 cameras in Real Time, you would need? 30FPS x 16 Cameras = 480Frames per Second.
Hard Drive Capacity the bigger the hard drive the longer the time of storage. Each DVR has a storage capacity,? 2M cctv offers a hard drive calculator to estimate the hard drive you need for given number of days of recording. Total storage capacity may vary depending on complexity of video scenes, system configurations and features used on the actual installation sites. Furthermore, the type of cameras that are connected to the DVR makes a difference, meaning higher resolution requires more space. The field of view will also affect storage capacity, the more complex the images the more space is required.
Recording Capability some DVRs support various recording options such as record on motion detection only, round the clock recording and scheduled recording.
Network Capability nowadays most digital video recorders have remote access capabilities, meaning from a remote location with internet connection login in to the video surveillance recorder to live view, playback, and backup video files.
Video files Backup is crucial with digital video recorders, there are many ways to backup video surveillance files, some of the common ways are: burning files on a CD or DVD, network backup, USB flash memory backups and external hard drive backups. Not all DVRs have the above backup methods as not all sites require a routine backup of video files.
Simultaneous Capabilities is defined on how many functions the DVR is capable of doing at the same time, most common DVRs come as Triplex, meaning it would record, live view and playback simultaneously without having to stop any of the other features. On the other hand, a simplex DVR would only allow one at a time, if you need to playback recorded video files you would need to stop recording first.
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