One purpose of region coding is controlling release dates. One practice of
movie marketing which was threatened by the advent of digital
home video was the tradition of releasing a movie to cinemas and then for general rental or sale later in some countries than in others. This practice was historically common because before the advent of
digital cinema,
releasing a movie at the same time worldwide used to be prohibitively expensive. Most importantly, manufacturing a
release print of a film for public exhibition in a cinema has always been expensive, but a large number of release prints are needed only for a narrow window of time during the first few weeks after a film's release. Spreading out release dates allows for reuse of some release prints in other regions. For example, the film
28 Days Later was available on DVD in the United Kingdom before it was released in theaters in the United States. Videotapes were inherently regional since formats had to match those of the encoding system used by television stations in that particular region, such as
NTSC and
PAL, although from the early 1990s PAL machines increasingly offered
NTSC playback. DVDs are less restricted in that sense. Region coding allows movie studios to better control the global release dates of DVDs. Also, the copyright in a title may be held by different entities in different territories. Region coding enables copyright holders to (attempt to) prevent a DVD from a region from which they do not derive
royalties from being played on a DVD player inside their region. Region coding attempts to dissuade importing of DVDs from one region into another.
PAL/SECAM vs. NTSC DVDs are also formatted for use on two distinct regional television systems:
480i/60 Hz and
576i/50 Hz (in analog contexts referred to as 525/60
NTSC) and 625/50
PAL/
SECAM). Strictly speaking, analog color television signal formats do apply to the digital domain, but the DVD system was originally designed to encode the information necessary to reproduce signals in these formats, and the terms continue to be used to identify refresh rates and vertical resolution. However, an "NTSC", "PAL", or "SECAM" DVD player that has one or more analog composite video output will only produce the corresponding signals from those outputs, and may only play DVDs identified with the corresponding format. NTSC is the analog TV format historically associated with the United States, Canada, Japan, South Korea, Mexico, Philippines, Taiwan, 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 (Brazil adopted the variant
PAL-M, which uses the refresh rate and resolution commonly associated with NTSC). SECAM, a format associated with French-speaking Europe, while using the same resolution and refresh rate as PAL, is a distinct format which uses a very different system of color encoding. Some DVD players can only play discs identified as NTSC, PAL or SECAM, while others can play multiple standards. In general, it is easier for consumers in PAL/SECAM countries to view NTSC DVDs than vice versa. Almost all DVD players sold in PAL/SECAM countries are capable of playing both kinds of discs, and most modern PAL TVs can handle the converted signal. NTSC discs may be output from a PAL DVD player in three different ways: • using a non-
chroma encoded format such as
RGB SCART or
YPBPR component video. • using
PAL 60 encoded
composite video/
S-Video—a "hybrid" system which uses NTSC's 525/60 line format along with PAL's chroma subcarrier • using NTSC encoded composite video/S-Video. However, most NTSC players cannot play PAL discs, and most NTSC TVs do not accept 576i video signals as used on PAL/SECAM DVDs. Those in NTSC countries, such as the United States, generally require both a region-free, multi-standard player and a multi-standard television to view PAL discs, or a converter box, whereas those in PAL countries generally require only a region-free player to view NTSC discs (with the possible exception of Japanese discs in most European countries, since they are in the same region - this means European region 2 users could import Japanese discs and play them on their players without any obstacles.) There are also differences in
pixel aspect ratio (720 × 480 vs. 720 × 576 with the same
image aspect ratio) and display frame rate (29.97 vs. 25). Most computer-based DVD software and hardware can play both NTSC and PAL video and both audio standards. Blu-ray players, which use up to 1080p signals, are backwards compatible with both NTSC and PAL DVDs. ==Implementations of region codes==