Apple Computer, Inc. has apparently decided that they needed to break compatibility between QuickTime movie formats, both upward and downward, in order for QuickTime 3.0 to move in the directions which Apple has in mind for it. The result is that .mov files created with earlier versions of QuickTime (QT) may not play in the QT 3.0 player, and .mov files prepared with QT 3.0 tools will not play in earlier versions of the QT player. Apple's response is that QT 3.0 can coexist on the same system with an earlier version of QT, thus allowing applications that are compatible with different QT revisions to still function.
However, you cannot configure the system so that the right revision player is called depending on the version of QT used to prepare any given .mov file. This is especially true for Web browsers. While you can have both the old and new QT plug-ins in the browser's plug-ins directory, the browser will only access one of the plug-ins when a .mov file is encountered in a Web page.
Additional problems occur because QT 3.0's plug-in for Web browsers also takes over playing MIME types that include .avi files, mpeg files and a variety of audio files. But QT 3.0 can only play files compressed with a set version of specific codecs (e.g. for .avi and .mpg files, Intel Indeo 4.4 codec, not Indeo 3.2 or 5.0x or 5.1). Even if you have the correct codec available from an earlier version of QuickTime, QT 3.0 appears to only work with the compressors with which it ships. So, with the plug-in from QT 3.0 installed for your Web browser, you will not only lose the ability to play many legacy .mov files, but also .avi, .mpg and some audio files compressed with versions of codecs or compressors not supported by QuickTime 3.0.
Apple support initially blamed Netscape and Microsoft for the fact that the MIME types for which QT 3.0 takes responsibility cannot be user configured. They said that the browser is responsible for deciding which plug-in to call for which file type. The point Apple did not make is that it is the responsibility of the plug-in to register with the browser for the file types it can handle, usually at plug-in load time. Clearly, the browser itself cannot know which plug-in to call to handle which file type unless the plug-in communicates that information to the browser in the first place.
As it turns out, Apple finally realized this point, and with QuickTime 4.0 has taken steps to provide users a little better control over which MIME types will be handled by QuickTime. This is especially true for Windows uses who can now change groups of MIME types that QuickTime takes over without having to edit the registry, something most users are not likely to, and should not attempt.
While this new 'file type association' choice in the QuickTime settings function is a welcomed addition to QuickTime 4.0, Apple needs to go further. This is because the file types are split into three groups - Windows file types, Macintosh file types and Internet file types. QuickTime can now obtain or relinquish controls of these grouping of files with a simple visual control. Clearly Apple could provide the means in its QuickTime settings tool to allow users to individually select which MIME types they want the plug-in to handle, and which types they do not want the QT plug-in to handle. But this configuration feature does not appear to be on QuickTime's horizon.
This leaves both users and Web site developers in a bind. Users either have to stay with the older version of the QT plug-in to be able to access the majority of .mov, .avi and .mpg files currently available, or they have to decide to give up that access and be content with only the QT 3.0 compatible files that show up as developers step-up to QT 3.0. If the user installs QT 3.0 over their older version, and they do not save a copy of the older plug-in file, they will permanently loose access to legacy media files. Links to Apple's QT download page primarily provide QT 4.0 as an option (7/99). While QuickTime 4.0 seems to remedy some of the problems with accessing legacy media (e.g. it can play .mov files compressed with Indeo 3.2), it still can exert itself as the primary application to access certain file types which the user may want associated with other applications.
Web site developers, on the other hand, are left with these options:
Rebuild all their .mov, .avi and .mpg files for QT 3.0/4.0 compatibility, and force the users to get the new plug-in. This has the potential of causing bad feelings on the users' part since, after the update, they will have difficulty with other sites' .avi, .mpg and .mov files.
Convert all .mov files to .avi or .mpg and post warnings that the media files on their sites are incompatible with QT 3.0/4.0. They will also remove links to Apple's QT download page so that users do not install QT 4.0 and loose access to the .avi and/or .mpg files into which the developers converted their legacy .mov files.
Initially, Apple was content to let the users and developers fight it out. According to the support pages on their Web site, when QuickTime 3.0 first appeared, Apple refused to supply any technical support for QuickTime 3.0 other than for installation problems. They had also removed the earlier versions of QT from their Web site (except for the 16 bit DOS/Windows 3.1 compliant version). So, while QT 3.0 eased the cross-platform issues as a Web media format, it created a major media format upward, backward and cross compatibility mess that both users and developers needed to consider when configuring their browsers and Web sites.
To their credit, Apple has moved to ease the burden some of the problems pose to both users and Web site developers. First was the move to add a modicum of control over QuickTime file type associations. Also, Apple technicians now reportedly participate in the discussions on the QuickTime 'Tech Exchange' message board at Apple's Web site. But, while Apple now allows download of either QuickTime 3 or QuickTime 4, if you need QuickTime 2.5 to view legacy material and you've not saved your QuickTime 2.5 install before upgrading, you are out of luck.
See QuickTime 3.0 Compatibility Example for an example of how QuickTime 3.0 complicates multimedia movie file viewing for one user.