Digital Video Recorders, otherwise known as DVRs, are generally available as standalone recorders or are PC based. PC based DVRs offer advanced features such as integration with existing security systems or unique features such as object counting, missing object detection, license plate recognition, and detect various suspicious behaviors based on user rules. Essentially, a DVR takes in a video or audio signal, digitizes it and stores the data on a digital hard drive. DVRs compress the video to make the file smaller and easily retrievable and exportable. New compression techniques such as JPEG, JPEG2000, H246 offer great image clarity, but take a succession of pictures and stick them together to create a video. MPEG4 is a modern video compression technology which offers a great combination of quality, storage size, and audio recording. The number of frames, or pictures recorded per second affects how the recorded video looks. For example, a DVR recording at 3 frames per second (3fps) will play video that has many gaps between the next picture, almost making a human's movement look like a robot. 30fps recording per camera is considered real time in NTSC video standard.The pixel size of recorded video is also important. The higher the number of pixels, the larger the screen size the DVR will record. For example,low resolution or real time is video recorded at 320x240 pixels. If you view this on a large monitor, the video will appear blocky as the monitor attempts to fill the whole screen. If you watch the same video on a PC, the size of the video will be small, about a quarter of your monitor screen but appear much clearer. Video recording quality, frame rate, and audio input all affect the recording time, but it is typically a good choice to capture video at the highest possible resolution and frame rate to create the best evidential video. DVRs are available with single, 2ch, 4ch, 8ch, 16ch, and 32 or more channels of video recording and differing amounts of audio inputs. DVRs can have alarm sensors attached to allow interfacing with external sensors and devices.

Network Video Recorders (NVRs) are essentially DVRs, but are used to collect IP video streams as opposed to directly connected analog video cables.