TV Broadcasting Standards

TV-wise, the world is divided into three main categories: those that use NTSC (National Television System Committee), those that use PAL (Phase Alternating Line), and those that use SECAM (Sequential Couleur Avec Memoire). NTSC is used in most countries in North- and South America and some countries in Asia. PAL is the main system in most of Europe and Asia. SECAM is used in France and many African countries. PAL and SECAM has several substandards, and for example Thailand uses the PAL B and PAL M broadcasting standards.

There are many technical differences between the various standards such as frame rate, number of lines per frame drawn on the screen, frame size, color encoding, sound sampling rate, etc. All these differences make the various systems incompatible with each other. However, in the digitized world of today most of the differences are easily overcome by software or by hardware chips. On these pages, we will confine our interest to those things that make conversion between broadcasting/video standards a not so simple task: frame rate, scan line rate and sound synchronization.

	NTSC	PAL	SECAM
Frames per Second	30	25	25
Lines per Frame	525	625	625
Cam Frame Size	720x480	720x576	n/a
Frame size is not part of the standards. However, most NTSC camcorders use 720x480 pixel while PAL camcorders use 720x576 pixel (so most DV tapes will be in either of these formats). We have added these figures to the table because we will use them later, when talking conversion techniques.

As is seen from the table, PAL and SECAM share the same frame rate. This makes the conversion between these standards a simple task and makes the conversion between either one and NTSC an identical task. Consequently, we will only investigate the conversions between PAL and NTSC since these are the most widespread broadcasting standards and the only ones used when talking DVD's.