PAL/SECAM vs. NTSC
DVDs are also formatted for use on two conflicting regional television systems: 525/60 (NTSC) or 625/50 (PAL/SECAM). Strictly speaking, NTSC, PAL and SECAM are all analog chroma-encoding formats which have no relevance in the digital domain (as evident in the conflation of PAL and SECAM, which are actually two very different analog color systems). These terms continue to be used (improperly) as a method of identifying refresh rates and vertical resolution.
NTSC is the analog color TV format historically associated with Canada, Japan, Mexico, Philippines, Taiwan, United States and other countries. PAL is the analog color TV format historically associated with most of Europe, most of Africa, China, India, Australia, New Zealand, Israel, North Korea, and other countries (and Brazil, but using the refresh rate and resolution commonly associated with NTSC). Some DVD players only play discs identified as NTSC or PAL, while others can play both standards.[9]
In general, it is easier for consumers in PAL countries to view NTSC DVDs than vice versa. Almost all DVD players sold in PAL countries play both kinds of discs, and most modern PAL TVs can handle the converted signal. However, most NTSC players cannot play PAL discs, and most NTSC TVs do not work with PAL video. Those in NTSC countries, such as in North America, generally require both a region-free, multi-standard player and multi-standard television to view PAL discs, or a converter box, whereas those in PAL countries generally require only a region-free player. There are also differences in pixel aspect ratio (720 × 480 vs. 720 × 576) and display frame rate (29.97 vs. 25). Again, NTSC discs play on over 95%[citation needed] of DVD systems worldwide, while PAL discs play on very few players outside of PAL countries.[9]
As of 2008, NTSC players and TV's are becoming increasingly capable of playing PAL/SECAM discs, thus beginning to equalize the ability for PAL machines to play NTSC discs and vice-versa. Needless to say, this reduces the need for a multi-region, standard player and TV (or converter box) to view either discs. Now consumers in both countries will most-likely require only a region-free player to view discs from anywhere across the globe (though a converter box or multi-standard system may be necessary if your TV and player can't handle a different format).
Most DVD PC software and hardware can play both NTSC and PAL video and both audio standards.