High Definition (or HD) provides a resolution that is substantially higher than that of standard-definition. This requires an HD television or computer monitor in order to be viewed. High-definition video has an aspect ratio of 16:9 (a.k.a. widescreen). Standard-definition television (SDTV) has usually a 4:3 aspect ratio.
High-definition television (HDTV) resolution is 1080 or 720 lines. In contrast, regular digital television (DTV) is 486 lines (upon which NTSC is based) or 576 lines (upon which PAL/SECAM are based).
To achieve true HD videoconferencing, it must achieve these standards:
•The bandwidth necessary to transmit the larger packets of data - typically 1 MB or above
•A resolution and a frame rate (usually 30 fps) that is defined as HD (in descending order):
- 1080p (1080 progressive scan lines)
- 1080i (1080 interlaced lines)
- 720p (720 progressive scan lines)
•An aspect ratio of 16:9 or widescreen (vs 4:3 aspect ratio with standard TVs)
•Visual equipment that will allow these HD resolutions be transmitted, with the available bandwidth necessary:
- HDTV monitor (e.g. Plasma, LCD)
- HD video camera and HD-capable codec