QuickTime is a multimedia technology developed by Apple Computer, capable of handling various formats of digital video, sound, text, animation, music, and immersive virtual reality panoramic images.

Overview

The QuickTime technology has three major components:

1. the QuickTime video file format itself — openly documented and available for anyone to use royalty-free
2. a media player which Apple makes available for free download on its website and bundles with each of its computers
3. software development kits available for the Macintosh and Windows platforms. These kits allow people to develop their own software to manipulate QuickTime and other media files

History

Apple released the first version of QuickTime on December 2, 1991 as a multimedia add-on for System 7. The lead developer of QuickTime, Bruce Leak, ran the first public demonstration at the May 1991 Worldwide Developers Conference, where he played Apple's famous 1984 TV commercial on a Mac, at the time an astounding technological breakthrough. Microsoft's competing technology — Video for Windows — did not appear until November 1992.

That first version of QuickTime laid down the basic architecture which survives essentially unchanged today, including multiple movie tracks, extensible media type support, an open-ended file format, and a full complement of editing functions. The original video codecs included:

• the Apple Video codec (also known as "Road Pizza"), suited to normal live-action video
• the Animation codec, which used simple run-length compression and better suited cartoon-type images with large areas of flat color
• the Graphics codec, optimized for 8-bit-per-pixel images, including ones which had undergone dithering

Apple released QuickTime 1.5 for Mac OS in the latter part of 1992. This added the SuperMac-developed Cinepak vector-quantization video codec (initially known as Compact Video), which managed the unheard-of feat of playing back video at 320*240 resolution at 30 frames per second on a 25MHz 68040 CPU. It also added text tracks, which allowed for things like captioning, lyrics etc at very little addition to the size of a movie.

In an effort to increase the adoption of QuickTime, Apple contracted an outside company, San Francisco Canyon Company, to port QuickTime to the Windows platform. Version 1.0 of QuickTime for Windows provided only a subset of the full QuickTime API, including only movie-playback functions driven through the standard movie controller.

QuickTime 1.6.x came out the following year. Version 1.6.2 first incorporated the "QuickTime PowerPlug" which replaced some components with PowerPC-native code when running on PowerPC Macs.

Apple released QuickTime 2.0 for Mac OS in February 1994 — the only version never released for free. It added support for music tracks, which contained the equivalent of MIDI data and which could drive a sound-synthesis engine built into QuickTime itself (using sounds licensed from Roland), or any external MIDI-compatible hardware, thereby producing sounds using only small amounts of movie data.

The next versions, 2.1 and 2.5, reverted to the previous model of giving QuickTime away for free. They improved the music support and added sprite tracks which allowed the creation of complex animations with the addition of little more than the static sprite images to the size of the movie.

QuickTime 2.0 for Windows appeared in November 1994.

The release of QuickTime 3.0 for Mac OS on March 30 1998 introduced the now-standard revenue model of releasing the software for free, but with additional features of the Apple-provided QuickTime Player and Picture Viewer applications that end-users could only unlock by buying a QuickTime Pro license code.

QuickTime 3.0 added support for graphics importer components that could read images from GIF, JPEG, TIFF and other file formats, and video output components which served primarily to export movie data via FireWire. It also added video effects which programmers could apply in real-time to video tracks. Some of these effects would even respond to mouse clicks by the user, as part of the new movie interaction support.

Apple released QuickTime 4.0 for Mac OS on June 8 1999. This added graphics exporter components which could write some of the same formats that the previously-introduced importers could read, though interestingly not GIF. It added the first version of the Sorenson video codec, and support for streaming.

QuickTime 4.1, released at the beginning of 2000, added support for movie files larger than 2 gigabytes on Mac OS 9 and later; and dropped support for 68K Macs. Users gained the ability to control the QuickTime Player via AppleScript.

QuickTime 5.0 for Mac OS appeared on April 23 2001. It added "skins" to the QuickTime Player and multiprocessor image compression support.

QuickTime 6.0 for Mac OS, released on July 15 2002, first included a version for OS X.

QuickTime 7.0 is due to be released on April 29 2005 with Mac OS X v10.4, featuring complete MPEG-4 compliance, H.264 codec, live resizing, and full-screen overlay.

Updates to the current version of QuickTime

The following table lists major updates to QuickTime 6.

QuickTime architecture

QuickTime consists of two major subsystems: the Movie Toolbox and the Image Compression Manager. The Movie Toolbox consists of a general API for handling time-based data, while the Image Compression Manager provides services for dealing with compressed raster data as produced by video and photo codecs.

QuickTime file format

A QuickTime file functions as a multimedia container file that contains one or more tracks, each of which store a particular type of data, such as audio, video, effects, or text (for subtitles, for example). Each track in turn contains track media, either the digitally encoded media stream (using a specific codecs such as Cinepak, Sorenson codec, MP3, JPEG, DivX, or PNG) or a pointer to the media stored in another file or elsewhere on a network. It also has an "edit list" that indicates what parts of the media to use.

Internally, QuickTime files maintain this format as a tree-structure of "atoms", each of which uses a 4-byte OSType identifier to determine its structure. An atom can be a parent to other atoms or it can contain data, but it cannot do both.

Apple's plans for HyperCard 3.0 illustrate the versatility of QuickTime's file format. The designers of Hypercard 3.0 originally intended to store an entire HyperCard stack (similar in structure to a complete web site, with graphics, buttons and scripts) as a QuickTime file.

This structure resembles that supplied by Microsoft's Advanced Streaming Format or by the open source Ogg and Matroska containers. However, QuickTime predated these other formats by many years.

QuickTime and MPEG-4

On February 11 1998 the ISO approved the QuickTime file format as the basis of the MPEG-4 standard. Supporters of the move noted that QuickTime provided a good "life-cycle" format, well suited to capture, editing, archiving, distribution, and playback (as opposed to the simple file-as-stream approach of MPEG-1 and MPEG-2, which does not mesh well with editing). Developers added MPEG-4 compatibility to QuickTime 6 in 2002. However, Apple delayed the release of this version for months in a dispute with the MPEG-4 licensing body, claiming that proposed license fees would constrain many users and content providers. Following a compromise, Apple released QuickTime 6 on 15 July 2002.

QuickTime players

Apple releases official media player software for Mac OS and Windows for free under the brand QuickTime Player. (Earlier versions simply used the name "MoviePlayer.") The player also comes with a number of media-editing and media-creation features, but users have to unlock these by purchasing a key from Apple, turning the media player into QuickTime Pro.

A number of companies utilise QuickTime for their software, for example:

• Apple's own iTunes jukebox audio player (designed for easy manipulation of audio media) utilises QuickTime for its playback technology
• copies of the Encyclopædia Britannica on DVD require QuickTime to play movie clips

Independent players for QuickTime 6 (MPEG-4) exist for many operating systems, and the FFmpeg library even supports the Sorenson video compression format. Apple, however, has licensed Sorenson technology exclusively.

QuickTime Pro

QuickTime Pro is a for-pay version of Apple Computer Inc.'s free QuickTime media player technology. It provides features, such as full-screen playback, MPEG-4 creation (see below) and other features not available in the free player.

QuickTime development

Developers can use the QuickTime software development kit to develop multimedia applications for Mac or Windows with the C programming language or with the Java programming language.

See also

• List of media players
• Comparison of media players

External links

• Apple - QuickTime: As one might expected of an official site, this URL presents general information on QuickTime (mainly for the purposes of marketing), and links to download the latest versions of the program.
• Apple's QuickTime developer site
• Apple - QuickTime Version Availability
• Apple - QuickTime File Format
• QuickTime Playback Compatibility Chart
• QuickTime history timeline
• Panoramas.dk - QuickTime VR-QTVR fullscreen panoramas