Hi guys,
Recently I read an article about digital video surveillance in China.
I excerpts the article below.

In recent years, China’s booming economy has brought great benefits to its economy, but also crime and traffic accidents have also increased. As security concerns escalate, digital video surveillance solutions are increasingly deployed in applications within public security services, law enforcement and transportation where video surveillance has a big part to play. There are two major types of video recording; one is called DVR or Digital Video Recorder, and the other requires installing a capture card on a DVR motherboard to encode analog to digital signals from cameras. All analog video/audio signals from cameras transmit data to the capture card via analog coaxial cables (BNC, RCA cables), and this means systems are limited by physical cable length. Network Video Recorder (NVR) is the latest video technology, and instead of traditional cameras, IP CAMs are used to transfer a digital signal directly over the Internet. Image compression allows large files to be transmitted over the network regardless of distance and location, and in full HD 1080P. The spread of the Internet means megapixel IP CAMs are becoming more common, and the NVR architecture has become the favored solution in surveillance applications.

If you are interested you can check here http://goo.gl/QzMGlg
Related video of digital video surveillance http://goo.gl/1JWnS1