Proprietary DVR
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DVRs, or Digital Video Recorders, are device which record video to a hard drive. The term Proprietary DVR refers to exclusive methodoligies used to maintain commercial control over the DVR format and prevent third party copying of a particular file. CCTV systems are used for the detection and recording of crime, but problems face the anaysits and law enforcement personnel who are required to obtain and process video recorded with proprietary DVRs.
The opposite of proprietary DVR is standard or PC based DVR. See How DVRs are Made
Currently there is no standard output for the security industry to follow. Because of this, analyists are forced to obtain a compatible "player" in order to view the video. Some proprietary DVRs are delivered to the end user in an executable player which allows for navigation. Some require the installation of the player. Still others simply require a CODEC to be available on the system that is playing, then it will become viewable in a common player such as Windows Media.
Some proprietary DVR systems offer more than one output format, such as the native format as well as a standard format such as AVI. Some also offer an NTSC output. Some security companies are reluctant to offer anything other than their proprietary format. Reasons cited for maintaining control over the file by making it conversion proof vary, but most companies will make "tamperproof" a sellable feature, while disregarding the work an analysist or court has to do in order to present the video.
Unfortunately another selling point of Proprietary DVR systems is compression. Video compression removes information in exchange for a smaller file size. By telling a store owner that he can archive 16 cameras running 24 hours a day for an entire year with little or no maintenance the owner becomes very interested. That is until he or she actually needs to extract an incident.
Another problem inherent in Proprietary DVR output is accuracy. There is a good chance that the video image as viewed has incorrect aspect ratio and/or color information. Color may be off simply due to the calibration of the monitor being used, but more than often color information is not recorded accurately. It is not very common to white balance security cameras unless it is done at set up.
Aspect ratios may also be recorded improperly and could actually be quite distorted. Aspect ratios on some players are sometimes user adjustable by simply draging the viewer in one direction or the other.
Contrary to attempts made by Proprietary DVR developers, it is possible to change virtually any DVR image into another format, but it cannot be done through digital conversion, such as changing a MPG2 to AVI. Instead it is done by intercepting the pixels sent by the proprietary DVR to the users monitor. There are a number of software available that will capture an area of a screen and generate an uncompressed file in a common format.
DVRs are here to stay. Gradually technology is improving and DVR systems are capable of having features that analog video could never provide. One feature is the ability to store metadata, such as point of sale information. Another feature may be for an event (movement, panic button, door/drawer opening) to trigger a system to record at a higher resolution. Perhaps the greatest feature is the ability to navigate directly to an area of interest. As storage drives become cheaper and larger, compression sacrifices are improving.
