QuickTime is Apple's programming library and API in C and Java, browser plugin and file format for the display, playback, editing and creation of all kinds of multimedia. It is certainly Apple's most important technology after the Mac OS
It is free to download, but distribution on CD requires a (free) licence from Apple, who will fanatically check the size of the logo on the CD, the colour, the size of the font used, how the installer is presented, etc...etc... Apple sell a Pro version that includes a version of QuickTime player that can edit and export files, but this is not required if you are using other editing tools that use QuickTime.
Official versions are available for Mac and Windows only, but there are several free software projects to offer support on Linux as well.
In May 1991, Apple announced the first version of QuickTime, available on Macintosh only. It was not until the web became more widely used, and partiularly when in 1994, Apple released a version for Windows, that QuickTime came into its own. The QuickTime plugin enabled web users to view content such as movies and sound that were starting to become available. Despite heavy competition from RealPlayer and Windows Media Player, QuickTime is more popular than ever. Over 100 million copies of QuickTime 4 were downloaded, and QuickTime 5 is on track to exceed that within its first year of release. A large proportion of this popularity is attributable to the fact that QuickTime is by far the most popular format for the delivery of movie trailers on the web. Trailers such as those for Star Wars : Episode I and Lord of The Rings were primarily available in QuickTime .mov format, and millions of people installed it in order to able to view these.
It should be stressed that QuickTime File Format is not a codec itself, but a format for delivering a large number of other codecs. The format is based on the Macintosh resource fork, and is represented by a tree-like structure. Data and metadata is stored atoms, which are just containers. Branch atoms contain related several leaf atoms which hold the data itself. The actual media data is stored in tracks, so, for example, a movie clip may contain a video track, an audio track and maybe several text tracks for subtitles/closed captions.
This format is very flexible, and openly documented, meaning third parties such as the QuickTime for Linux project can create software that reads and writes .mov files without the need for QuickTime to be installed. The format also forms the basis for the MPEG 4 standard.
QuickTime supports a very large number of codecs and formats, and developers can create plugins to enable further formats. These can be automatically loaded when a file requiring them is encountered.
These are the standard formats and codecs supported in QuickTime:
Import File Formats
Export file formats
QuickTime supports a large number of video compressors or codecs, but the killer codec is certainly Sorenson. This is licenced exclusively to Apple and is a large factor in many decisions to choose QuickTime over other platforms for video. The Sorenson codec gives very good quality and relatively small filesizes, and is probably the thing that Linux and other non- Windows or Mac users miss most through not having official QuickTime. It is truly a great codec, Apple guards it jealously, with good reason. The full list of codecs supported for input and output, is below:
QuickTime also supports SMIL presentations, and Apple has announced that support for official MPEG 4 will come in the next version.
QuickTime is also fully scriptable, with its own language, QScript. this can be embedded with QuickTime movies, enabling developers to create mini applications that run through the QuickTime player. A movie can also hold an embedded skin track that can turn the QuickTime player into a easily-customisable 'shell' for your application.
As well as the ever-popular QuickTime plugin and ActiveX control, and the much-maligned QuickTime player, many popular applications have QuickTime at their core, particularly on the Mac. Most video editing apps such as Adobe Premiere, as well as Apple's own iMovie and Final Cut Pro are based on QuickTime.
File format lists from: http://www.apple.com/quicktime/specifications.html