There are three types of CCTV cameras in the market:
Conventional Analog CCTV cameras
This is a type of CCTV camera which has existed for a long time. These cameras’ resolution is in “TVL” - TV Lines. The video signal is analog. Here is the demo video from conventional analog CCTV camera: CCTV Video Demo of SafeTrolley 1200I Analog CCTV Camera
HD analog CCTV cameras
This is a type of CCTV camera which is to replace the conventional analog CCTV camera. The video image resolution can be 720P, 1080P, etc. The image sharpness is much better than conventional analog CCTV cameras. But it is still considered analog signal. Those commonly seen HD-TVI, AHD, HD-CVI refer to different standards of HD analog CCTV camera. Here is the demo video from HD analog (HD-TVI) CCTV camera: CCTV Video Demo of SafeTrolley HD-TVI CCTV Camera (1080P)
IP CCTV camera
This is fully digitalised CCTV camera. Because of it’s digital nature, compression and decompression is achieve at the camera level. Image quality, sharpness is much greater than conventional analog CCTV cameras, and better than HD analog CCTV cameras. Here is the demo video from IP CCTV camera: CCTV Video Demo of SafeTrolley S-Series HD IP CCTV Camera