Television Standards Conversion - Overview

Overview

Perhaps the most technically challenging conversion to make is the PAL to NTSC.

• PAL is 625 lines at 50 fields/s
• NTSC is 525 lines at 59.94 fields/s (60,000/1,001 fields/s)

The two TV standards are for all practical purposes, temporally and spatially incompatible with each other.

Aside from the line count being different, it is easy to see that generating 60 fields every second from a format that has only 50 fields might pose some interesting problems.

Every second, an additional 10 fields must be generated seemingly from nothing. The converter has to create new frames (from the existing input) in real time.