Digital Video Recorder

DVR (Digital Video Recorder): An analog and/or IP based recorder is a consumer electronic 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. A digital video recorder configured for physical security applications record video signals from closed-circuit television cameras for detection and documentation purposes. Many are designed to record audio as well, whether at the camera or as a separate apparatus in an isolated area. 
DVRs have evolved into devices that are feature rich and provide options that exceed the simple task of recording video images that was previously done through VCRs. Any good DVR CCTV system provides a multitude of advanced functions over VCR technology including video searches by event, time, date and camera. There is also much more control over quality and frame rate allowing disk space usage to be optimized and the DVR can also be set to overwrite the oldest security footage should the disk become full. 
In some DVR security systems remote access to security footage using a PC, Smart Phone, or tablet can also be achieved by connecting the DVR to a LAN network that has an internet service. Some of the latest professional digital video recorders include video analytics software, to enable functionality such as ‘virtual alarm system’ or even the detection of differing objects on the scene. 
Security DVRs may be categorized as being either PC-based or a stand-alone unit. A PC-based DVR’s architecture is a classical personal computer with video cards designed to capture video images. A stand-alone DVR is specifically designed as a digital video recorder with its own operating system and application software contained in firmware or built in flash memory.