Analog Closed-Circuit Television cameras record pictures or videos as analog signals. Most of old surveillance cameras are analog cameras. This type of camera records directly onto a video tape recorder. In order to save recordings to a PC, the analog signal must be converted to a digital format; this can be done with a video capture card.

Digital CCTV cameras directly capture images and videos as digital signals. The signals are compressed and encoded into a standard video format such as MPEG. Digital CCTV cameras usually record videos onto a hard drive or a storage server.

An Internet Protocol camera or network camera is a type of digital video camera that can send and receive data via a computer network. This type of camera has become increasingly popular among homeowners and business owners in the last few years because of steep price drop. A webcam can also be considered as a network camera because it can send or receive data via a computer.

Security cameras themselves are not completely secure. They can fail due to dust, smoke, fog, loss of power, or damage. They are also easily susceptible to tampering. If a security camera records data onsite, both the camera and the recorded data can be destroyed – by intruders, burglars, or anyone else who wants the data gone forever.

Many security cameras now support motion detection - a technology that triggers recording only when something changes in the scene. Motion can be detected by image changes or sound changes. Many security cameras can only detect image changes. As minor scene changes can occur due to events such as natural light changes or wind changes, many security cameras allow you to configure a “threshold”. By setting a higher threshold, minor scene changes will be ignored and only scene changes that reach the “threshold” will be recorded. Motion detection is very useful if you want to significantly reduce bandwidth and storage usage.

One of the main usages of a security camera is to monitor night-time scenes. If the scene is not well lit, it is recommended that you use a camera with night vision capability. Those cameras use an infrared spectrum of light at night and can take pictures of objects in the dark.

Wireless security cameras transmit video and audio signals wirelessly to a receiving device. There are analog and digital types of wireless cameras. Digital security cameras have become much more popular recently because they can be accessed over the Internet.

FTP cameras are a type of IP cameras that support uploading of recorded images and videos to an FTP server. Almost all modern IP cameras support FTP upload. FTP offsite storage is by far the most popular way to store image and video files from a security camera.

Most security camera systems can store recorded images and videos to a tape, hard drive, or onsite storage server. However, storing data in this manner leaves it susceptible to tampering and damage by intruders. For better protection and security, offsite storage is the best solution.

The required amount of storage is dependent on your camera’s image resolution, frame rate, compression ratio and days of retention. Setting up your camera to use motion detection can significantly reduce storage usage.

Security cameras can generate a large amount of data. The amount depends on the compression ratio, images captured per second, and image size. Most cameras provide a limited amount of storage space; therefore, recordings are usually kept for a preset amount of time before being overwritten by new images.

An analog security camera usually supports PAL (768x576 Pixels) or NTSC (720x480 pixels) format. A digital security camera can support many different image resolutions, e.g. 320x240, 640x480, 800x600, 1280x960, and more.