Video is the rapid playback of many still images synchronised with audio. This can lead to large amount of data required for video.
The first step in digital video is digitization, the capture of analogue video from a video playback system, to be converted into a digital stream.
Once video is in a format inside the computer it can be edited and modified in limitless ways.
Due to the repetative nature of the scenes in video, this allows for compression in the temporal space, many video encoding systems exist and as CPUs become faster more systems will become available. Conversion from one CODEC to another is known as transcoding.
Video can come from numerous sources, including other digital capture devices (digital cameras) or analogue sources such as VTRs
In the Analogue space video is most commonly represented by 3 signals. (not including synchronisation) These 3 signals are categorised into 2 types. Luminance or the brightness of a pixel. And chrominance, the colour of the pixel, 2 signals are required for colour information.