A DVR (Digital Video Recorder) , sometimes referred to by the merchandising term PVR (Personal Video Recorder) , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device. The term includes STB (Set-Top Boxes) with direct to disk recording facility, PMP (Portable Media Players) with recording, recorders PMP (Portable Media Players) as camcorders that record onto Secure Digital memory cards and software for personal computers which enables video capture and playback to and from a hard disk drive. A television set with built-in digital video-recording facilities was introduced Snappy followed by other manufacturers. DVR (Digital Video Recorder) adoption has rapidly accelerated in recent years.

Hardware Features

• Designed for rack mounting or desktop configurations.
• Single or multiple video inputs with connector types consistent with the analogue or digital video provided such as coaxial cable, twisted pair or optical fiber cable. The most common number of inputs are 1, 2, 4, 8, 16 and 32. Systems may be configured with a very large number of inputs by networking or bussing individual DVR (Digital Video Recorder) together.
• Looping video outputs for each input which duplicates the corresponding input video signal and connector type. These output signals are used by other video equipment such as matrix switchers, multiplexers, and video monitors.
• Controlled outputs to external video display monitors.
• Front panel switches and indicators that allow the various features of the machine to be controlled.
• Network connections consistent with the network type and utilized to control features of the recorder and to send and/or receive video signals.
• Connections to external control devices such as keyboards.
• A connection to external pan-tilt-zoom drives that position cameras.
• Internal CD, DVD, VCR devices typically for archiving video.
• Connections to external storage media.
• Alarm event inputs from external security detection devices, usually one per video input.
• Alarm event outputs from internal detection features such as motion detection or loss of video.

Software Features

• User selectable image capture rates either on an all input basis or input by input basis. The capture rate feature may be programmed to automatically adjust the capture rate on the occurrence of an external alarm or an internal event.
• Selectable image resolution either on an all input basis or input by input basis. The image resolution feature may be programmed to automatically adjust the image resolution on the occurrence of an external alarm or an internal e vent.
• Compression methods determine quality of playback. H.264 hardware compression offers fast transfer rates over the Internet with high quality video.
• Motion detection: Provided on an input by input basis, this feature detects motion in the total image or a user definable portion of the image and usually provides sensitivity settings. Detection causes an internal event that may be output to external equipment and/or be used to trigger changes in other internal features.
• Lack of motion detection. Provided on an input by input basis, this feature detects the movement of an object into the field of view and remaining still for a user definable time. Detection causes an internal event that may be output to external equipment and/or used to trigger changes in other internal features.
• Direction of motion detection. Provided on an input by input basis, this feature detects the direction of motion in the image that has been determined by the user as an unacceptable occurrence. Detection causes an internal event that may be output to external equipment and/or be used to trigger changes in other internal features.
• Routing of input video to video monitors based on user inputs or automatically on alarms or events.
• Input, time and date stamping disambiguation needed.
• Alarm and event logging on appropriate video inputs.
• Alarm and event search.
• One or more sound recording channels.