Full Motion Video (FMV) is a popular phrase to describe a video game concept popular in the early 1990s. It is as the name suggests - videos with "full motion" (i.e. the video updates and changes every time the screen is refreshed, typically about 30, 50 or 60 times as second depending on the game).
It is not entirely certain where the phrase orginates from, nor is there an exact definition of what "full motion video games" should refer to, however it is typcally used to describe certain video games of the late 1980s and early-to-mid 1990s, which are centered around the concept of being able to decode and stream digital video in real time (as well as providing a gameplay experience).
Today, decoding and streaming video formats within video games is commonplace, but are usually used for non-interactive sections (e.g. cutscenes, menu backgrounds, etc.). For a while, it was considered part of the gameplay experience. FMV is considered different to the traditional form of displaying video game graphics through the use of sprites or polygons - it was a short-lived fad designed to attract the attention of consumers, giving the illusion of significantly improved graphics when compared to rival methods.
Full Motion Video became common within video games in the early 1990s. A previous generation had enjoyed experiments on LaserDisc-based arcade systems (Dragon's Lair, Space Ace) however the hardware was deemed far too expensive to produce for home video game consumers at the time. Furthremore the LaserDisc format ended in tragedy and failed to win over the hearts and minds of VHS owners.
With the advent of compact discs, developers were given enough room to store (low quality) videos, and a generation of new CD-based video game consoles (including the Sega Mega-CD) had the power to stream these videos in real-time. Many developers took advantage of this and attempted to create "revolutionary" games which could now both look and sound superior to their cartridge-based rivals.
For a while, the idea was popular, particularly with North American consumers. Entire systems were built or conceptualised to handle FMV games and to many it was seen as "the future". The general public had different ideas however, and though the likes of Night Trap had initially proved popular (if not just for the controversy that surrounded it), most FMV games failed to capture its success. Unlike a game built with traditional methods, a pre-rendered video cannot be changed in real-time, and thus it is very difficult for the player to maniupulate their surroundings in any way.
Many FMV games are very linear in their approach - unlike a game of Sonic the Hedgehog where the player can adjust the position of Sonic ensuring no two play-throughs are exactly the same, most FMV games were destined to always pan out the same way, with relatively little choice involved. FMV games are often built up of "quick-time events", i.e. rely on buttons to be pressed at specific times (or cursors moved to specific areas of the screen) to advance. Others are essentially simple mazes where the player merely chooses a path - he or she does not physically move the character to a goal.
Some FMV games used the technology to their advantage, such as Cyan World's Myst. It is a good choice for adventure games, however this genre was on the decline in the mid-1990s in favour of more action-packed scenarios and has not yet recovered.
FMV games as a concept started to be phased out in the mid-1990s as sales began to slump. With them went entire companies, most notably Digital Pictures who invested heavily in the idea. Today, FMV games are almost non-existent, though some still show up in the form of DVD extras.
Sega (and others) heavily marketed the concept of full motion video games for the Sega Mega-CD, particularly in North America where 60% of the system's launch titles were FMV games. Many popular Japanese RPGs for the system were barred from entering the states due to fears they might not sell in the region. All six Sega Mega-CD 32X titles are "enhanced" FMV games. It was a heavily stressed feature, and considered one of the main reasons the system failed to make the same amount of impact as expected.
The Mega CD in fact struggles with the concept of full motion video, and compares unfavorably to many of its rivals - the TurboGrafx-CD, Atari Jaguar CD, Neo Geo CD, Philips CD-i, FM Towns Marty, Panasonic 3DO and Amiga CD32. This is because the Mega CD suffers from the same restrictions as the Sega Mega Drive in terms of on-screen colours - only 64 colours can be outputted on screen at once, which often leads to grainy, low quality video in which detail is lost. The Sega 32X add-on can increase the colour count significantly, but this required extra investment - typically more than any of the consoles mentioned.
FMV games were less common in Japan and Europe.
FMV games are far rarer on the Saturn, but the superior hardware means that the games perform better than on the Mega CD. This generation of consoles spurred the industry to move away from FMV games and into polygon-based 3D visuals.