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Home > Camera Equipment > Video Recording Video-recording: is it needed for home surveillance?
Analog Video Tape The expression Video-recording is employed here in a larger meaning. Images can be recorded also on new devices based on recent digital technology, and in future still more advanced development may come to the market. Therefore Video-recording System in this exposition means whatever method used for saving and retrieving images. The disadvantages usually attributed to tape based VCRs are that the sharpness is inferior to that of digital recording, that the tape recording quality is deteriorating during long storage time of tapes, and that the devices need some maintenance and scheduled cleaning. A more important thought is probably that this technology, although possibly more economic just now, risks to become slowly obsolete so that in time it may become difficult and expensive to maintain and to fix the equipment. What should be considered is if these drawbacks are important for a simple home surveillance system against the advantages of proven technology and relatively inexpensive setup. An economic solution uses a special controller that operates a normal home VCR upon movement detection.
VCRs specially designed for CCTV can record video images either in real-time or in time-lapse modes. In the real-time recording mode, the tape moves continuously at the same speed as home VCRs for 2 to 6 hours and captures 25 or 30 pictures per second (depending on the frequency of the electric power supply). This produces high quality recordings, but requires operators to change tapes quite often. A special VCR can record 24 hours of video on a single tape at 20 pictures per second. It approximates a real time recorder because running 20 pictures per second provides almost continuous movement perception. (The actual standard frequency of projected films used to be 24 frames per second). The technique of time-lapse Video-recording makes it possible to record selected video images for longer periods of time by running the videotape intermittently. This excludes audio recording at the same time but it is not a great loss because, as explained elsewhere (see Camera Audio), it is not permitted for home surveillance and may even be illegal. Time lapse VCRs record a frame every few seconds for more economic use of tapes. With proper programming they can capture from 12 to 960 hours of video frames on one 120 minutes tape, and even up to 1280 hours with longer tapes. However, limiting the number of pictures recorded per second reduces information quantity and quality. Besides real time Video-recording, additional features sometimes available on this kind of recorders are time and date marking generator and fast time and date search on play back. 7729R 64-Hour Time-Lapse VCR is a convenient dedicated recorder for one camera, that can be started by motion detection alert. If it is fed however by a Quad Processor linked to 4 Cameras, then it will be able to record the split screen as is, with 4 reduced size images. Any of the following are suggested Quad Processors for this use:
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Another option to conserve recording time is that of using an external alarm, movement sensing devices or image analyzing software, to start actual recording upon observing action. This feature saves recording media by operating at real time speed only when the image is changing, and running for two minutes or as required, before going back to stand-by state.
Note that shorter recording saves also reviewing time at play back, by limiting the attention span to view recorded events that require further investigation. (See Video Surveillance). Digital Video Two other options of Video-recording should be considered before deciding which is the most appropriate in a given situation. With both these solutions, which in fact process digitized video images, file compression allows very dense utilization of the storing volume available, making possible recordings of 30 days productions and even more. Personal Computer A PC based digital video system includes a computer, video capture cards and special software. This solution, although requiring some computer skills, has the additional advantage of being accessible through the internet, if needed. The 4-CAM Color Quad w/USB 2.0 DVR Capture - 7757U is a nice solution worth being explored. It works with 4 cameras and your Pentium PC to do all you expect from an integrated system and costs much less than integrated systems or standalone devices. It provides motion activated recording. According to Smarthome Technical Support this instrument accepts output from Color Cameras with embedded IR (Infra Red) illuminators like those presented elsewhere in this website.
Many features provided by the PC environment are easily exploited by suitable programming. Future expansion to a larger number of cameras is possible. If the PC is dedicated to home surveillance, then a regular analog Camera Monitor is redundant and not really necessary. Video-recording hardware device A digital Video-recording unit (DVR) greatly improves recording frame rate and recording resolution. Picture resolution can be obtained at a much higher quality using a DVR than using an analog videotape recorder, that usually lacks high resolution. DVR recording resolution improves also play back quality. DVR with built in multi channel multiplexer are now available with recording frame rates of up to 480 FPS (frames per second). A DVR recorded picture maintains its premium quality in time. All these advancements, however important, come at a price, which may not be warranted for the simplest home surveillance installations. The following 4 channel standalone DVR provides many useful features, including Quad Processor display and file compression (MJPEG format), permitting easy adaptation to particular user requirements, although it is not designed for Internet connection. For exploring the options available and suggested usage, interested readers are urged to refer to Product Brochure and Owner's Manual downloadable from the linked page.
The following 77304 4-CH Digital Video Recorder w/80G Drive is a high end product which provides integration advantages and it includes a hard disk drive with 80GB storage, a four channel multiplexer for displaying the output of four cameras on the same monitor, PTZ camera control and Internet connectivity for image transmission at a distance. It also includes motion detectors capable of starting the recorder. You would not need to use your PC.
The instrument can display continuous camera viewing while Video-recording at the same time. Compatible with most analog Monitors and with computer digital screens accepting S-video signals. For exploring options available and suggested usage, interested readers are urged to refer to Operating Instruction Manual and Spec. Sheet downloadable from the linked page. The programming capabilities are in part hard wired and in part software based. All programs running the application are stored internally. No computer skills are required. The Video-recording unit is operated by a hand held remote control unit, similar to those used for different appliances. It can be remotely accessed via Internet if required. Future expansion however is not easily implemented. It should be added that if monitoring through the Internet from a distance is required, special cameras are available for direct connection to the Internet, with no dedicated PC at the camera remote location, only at the viewer's end.
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