QuickTime almost single-handedly kick-started the computer video revolution. At one point, it was virtually synonymous with the concept, much like Jeep is for off-road vehicles and Hoover for vacuum cleaners. It was the first video format to be a container for different types of multimedia. This keeps it flexible, allowing it to be used for low-bandwidth streaming video all the way up to high-quality editing. The specific codec used inside the QuickTime file dictates its intended use.
The QuickTime container uses tracks for different media types, so can even include interactive buttons, bitmap graphics, text, QuickTime VR panoramas, 3D objects, MIDI music, animated sprites, information to assist streaming, and of course video and audio, plus a few more. So to call QuickTime just a video file format is doing it a bit of an injustice.
In the past, QuickTime contained many similar video codecs to Video for Windows (see the next page), such as Cinepak. However, more recently Apple obtained exclusive use of some important codecs, in particular Sorensen Video Pro in 1998. This highly efficient interframe codec has become particularly popular for streaming media, as it offers very good video quality at low data rates. However, Windows Media Video has caught up in the last couple of years, and Apple has turned its attention to MPEG-4 H.264 AVC (more on that next week).
With its container system, QuickTime can compress video to all kinds of formats, even streams of still images. Various flavours of DV can be embedded, as can M-JPEG (page 4), and 3GP for mobile phones. Alongside the latest versions of the Sorensen codecs, and MPEG-1 and MPEG-2, QuickTime 6 added its own take on MPEG-4, and QuickTime 7 extended this to H.264. Audio formats include QDesign's Music 2, Qualcomm's PureVoice, MP3 and WAV, but the main option is now MPEG-4 AAC, as used in the iTunes store. So when you come across a MOV file, what's actually inside it could be a huge variety of different media formats.