Effective video compression is the key enabling factor in the emergence of digital video surveillance as a replacement for traditional CCTV systems based on anolog VCRs.

When evaluating different types of compression it is important to consider not only the effectiveness of the compression, but also on what system the video is going to be played. If the compression format is a well known type, it is both likely to be supported by mainstream viewers (such as, Microsoft's Windows Media Player) and can be archived for use in the distant future. Proprietary compression algorithms often offer superior performance but come at a price of compatibilty. Many proprietary solutions offer a conversion tool, but this tool often takes a significant amount of time to run.

The most common video compression formats used in video surveillance are:

   M-JPEG

   MPEG-4

Over time these will be supplanted by the new standard:

   AVC

Finally, there are many DVRs that take an alternative approach to storing and compressing video. These DVRs store a series of JPEG images individually and replay them on demand. An advantage of this approach is that is possible to play back the video in almost any Web browser. The vendor will likely use some clever JavaScript routines to present the JPEG images in sequence to the user. The specific advantage is that there no need to download a browser plugin (activex) or any other code onto your computer to view the video. The disadvantage is that usually the frame rate is quite low (i.e. greater than 1 second).