Not all DVD's play on all DVD players. There are actually two compatibility issues one needs to consider: video standards--the type of video signal used in your country; and DVD region encoding--technology employed by DVD manufacturers to discourage the import and export of DVD's.

Video Standards
Dating back to the establishment of broadcasting standards in the early days of television, the standard format of video signals differs in different parts of the world.

This is important to note because even though the physical format of the media may be the same (VHS tapes are available around the world and will physically fit and operate in VHS VCR's), the signal format may be different; playing an NTSC videotape in a PAL VCR (and vice versa) will yield an unwatchable signal.

To play a PAL DVD in the land of NTSC, you will need:

A PAL-capable DVD player and a PAL-capable TV

Or

A PAL-capable DVD player, a PAL->NTSC converter box, and an NTSC TV

Or

A PAL-capable DVD player with built in PAL->NTSC conversion, and an NTSC TV

As mentioned above, there is another video standard called SECAM that is widely used in France. SECAM is similar enough to PAL that PAL video can be viewed on SECAM equipment, but SECAM video cannot be viewed on PAL equipment (nor NTSC, of course). The French editions of Battle Royale are in PAL.

DVD Regions

For economic, copyright, and distribution reasons, when the DVD format was created the people in charge decided to divide the world up into different regions, so that DVD's from one region cannot be played in DVD players of another region.

The regions are (generally) as follows:
Region 1: The U.S. and Canada
Region 2: Europe, South Africa, the Middle East and Japan
Region 3: South Korea and South-East Asia
Region 4: Mexico, Central and South America, Australia, the South Pacific
Region 5: Africa, South Asia, Russia
Region 6: Mainland China

Some DVD's don't have region-encoding. These "region-free" or "Region 0" discs can play on any DVD player regardless of region, BUT the equipment must be the appropriate video standard...

So what does this mean? Well, for some viewers, there are added limitations to watch out for. Even though Japan and the UK are both in Region 2, Japanese NTSC DVD's will not work in most UK DVD players, which are PAL-only. And even though the UK PAL DVD's of Battle Royale are region-free, they will not play in most U.S. Region 1 players because of the incompatible video standards.

For information on region-switchable and multi-system DVD players, check out sites like www.dvdrhelp.com.

What's DVD-5 and DVD-9?

There are two types of DVD's. DVD-5's store their data on one layer of recordable media, while DVD-9's have a second, semitransparent layer. This allows for nearly twice as much information on DVD-9's as there are on DVD-5's, which translates to more video data (and a better image) and more room for extras (additional soundtracks, additional angles, special features).

What's PAL Speed-up?
Motion picture film runs at 24 frames per second. NTSC, the video standard in the United States and Japan (see video standards) runs at approximately 30 fps, and PAL, the video standard in the UK and Europe, runs at 25 fps. In order for films to be converted to video, professionals distribute the 24 frames over the 30 frames of NTSC by breaking them down into the 60 component fields that comprise them and distributing the frames over them so that one film frame takes up three fields and the next frame takes two.

Anyway, I'm getting too technical there but the point is with NTSC, there's a way to convert film images to video without noticeable side-effects like stutter or "tracer" effects. PAL, on the other hand, does not. The most practical way to convert 24 fps film to 25 fps PAL is to speed up the film during the conversion. As a result, for every 24 seconds of PAL video you lose 1 second of real running time, which adds up to quite a few minutes of the total running time of a feature. This is why the runtime of the original Tartan release of BR is significantly shorter than the real running time of the film--nothing was cut out, but things are played slightly faster, with the soundtrack just slightly higher in pitch.

The Tartan UK release of the Special Edition of BR, even though it's in PAL, doesn't have the PAL speed-up (despite what it says on the packaging). This is because the feature was converted to PAL not from the original print, but from an NTSC version of the film. The downside is that the image suffers from a bothersome "tracer" effect as a result of the NTSC-to-PAL conversion.