Characteristics of Digital Video
For video to be played and processed in computers it needs to be converted from analogue to digital representation. Video Digitization is achieved just like audio digitization by sampling the analogue video signal at a preset frequency and subsequently quantizing the discrete samples in digital format. This is done with help of an analogue to digital converter or ADC.
There are two kinds of possible digitization or digital coding – Composite coding and Component coding.
Composite coding: In composite coding, all signal components taken together as a whole are converted into digital format.
Component coding: In component coding, each signal component is digitized separately using different sampling frequencies (13.5 MHz for luminance, 6.75 MHz for chrominance).
It is based on whether the ADC is inside a digital camera or in an external unit or inside the computer. There can be three types of digital video systems.
1. Digital Camera-based System
2. External ADC System
3. Video Frame Grabber Card-based System
Advantages of Digital Video:
i. Storing video on digital devices memory ready to be processed (noise cancellation, cut and paste, size and motion control and so on) and integrated into various multimedia applications.
ii. Direct access which makes non-linear video editing (Audio mixing, adding text, titles and digital effects, etc).
iii. Repeated recording without degradation of image quality.
iv. Ease of encryption and better tolerance to channel noise.