Analogue and IP Cameras
As with any imaging device, the analog CCTV camera has a sensor which captures the video image. The resolution of the sensor varies but for reasons which will be described later, it is limited to 720×575. This is 720 pixels across the screen (horizontal resolution) and 575 up and down (vertical resolution). The video is captured at 60 intervals called “fields” and transmitted to the receiver. Two fields together are called a “frame.” This is called interlaced transmission. More on this later.
An IP camera has an image sensor much like the analog camera. However, once it has captured its image, it transmits it as “data” over a network connection. That data is in the form of compressed video frames sent over standardized networking protocol used for computer applications which is where it gets its name. “IP” stands for Internet Protocol which is the low-level language used to transmit data between computers in your home and the Internet. What this implies then is that the IP camera is like a little computer that you connect to, to access your video. Indeed, IP cameras are computers and run operating systems not all that different from your PC. Where they differ is that they are fixed function and their programming cannot be extended by the user.