The proliferation of digital media has had a substantial impact on the way that movies, music, and other media are created and distributed. The production process for audio and video media has changed radically in response to the availability of digital video and audio capture devices and editing systems, as well as due to the ability of media producers to collaborate electronically. But, although the shift to a digital production process has been a boon for creativity and productivity, it has also created new threats of piracy and unauthorized distribution of the inputs to production (e.g. un-edited video footage, concept art, scripts, storyboards, etc.). This is because the same file formats and communication systems that simplify collaboration in the production process may also be used to facilitate unauthorized uses of inputs to production. For example, a person working on a large film production project can just as easily post un-edited or partially edited footage on the Internet where it is available to any and all potential viewers as he can post it to a private intranet as part of his collaboration with others working on the project. Even when all people who are authorized to access a particular input to production can be trusted, there exists a threat that a third party will compromise the digital systems they use to communicate and collaborate to gain unauthorized access to it.
Similar threats of piracy and unauthorized distribution exist with respect to the final products of the production process. For the same reasons that electronic distribution of media, whether via the Web or thorough proprietary services (e.g. Apple Inc.'s “iTunes Store”) is efficient for distributors and convenient for consumers, it is also subject to intellectual property (IP) theft, since digital media distributed electronically is easily redistributed from authorized people and devices to unauthorized people and devices. A digital video downloaded from the Web by an individual authorized to view it can easily be sent to another, unauthorized individual over an instant messaging system, a peer-to-peer network, email, or other electronic file sharing and communication channels. Even media distributed through conventional channels—such as movies distributed on DVD—is subject to IP theft through the use of technology that allows computer users to “rip” media from one format and storage medium (e.g. CD-format audio on a CD) to another (e.g. MP3-format audio on a user's hard drive). Once media has been “ripped” from a conventional storage medium, it can be redistributed just as easily as media that is distributed electronically in the first place.
The term “digital rights management” (DRM) describes technologies that protect the IP rights of creators and owners of digital media by preventing or impeding its unauthorized use and distribution. This is most often accomplished by the use of computer cryptography to obscure the contents of digital media files so that unauthorized users and programs cannot play them back.
There is a need among creators and owners of digital media for a DRM technology that is (1) sensitive to the context in which media is played back and (2) flexible enough to allow the rules of access to or re-distribution of a piece of media to be changed after it is initially distributed. Context-sensitive DRM determines whether a media file can be played back each time it is accessed by a user. In doing so it may consider, among other factors, when the file was initially distributed to the user, how it was distributed, the location of the user at the time the file is accessed, the software program or the hardware device being used to access the file, and the number of times the file has been accessed. Flexible rules of access allow creators of digital media and owners of rights to digital media to change the way in which access to a particular file is determined after the file has been distributed, or to revoke access completely.
Apple Inc.'s QuickTime file format is one of the most popular digital media formats. Files using the QuickTime file format are called “movies” and may contain various combinations of audio, video, and other types of information. A QuickTime movie contains one or more “tracks”—segments of audio, video or other data that are played simultaneously or consecutively when a user accesses the movie. The audio or video data in a track may itself be stored in one or more formats, or “encodings,” that determine how a particular image or sound is represented in binary, and thus how audio or video is represented in the movie file. A QuickTime movie comprises a “header” describing the tracks that the movie contains and how the tracks are encoded, as well as one or more separate blocks of “movie data” comprising the actual binary representations of the tracks' contents. For audio and video tracks, track contents are divided into “samples”—instantaneous representations of the audio or video signal contained in the track at consecutive moments in time. The header of a QuickTime movie, in addition to describing the number and type of tracks it contains, indicates where in the movie file each sample for each audio or video track is located. The audio, video and other tracks contained in a QuickTime movie are accessed, or “played back,” through one of several software programs that support the QuickTime format or the related MPEG-4 format. Many programs that support the QuickTime format make use of a “plug in” architecture that allows users to add support for new audio and video encodings by installing sets of machine language instructions for playing back tracks that use those encodings. Such sets of instructions are called “plug-ins” because they can be “plugged in” to existing programs to expand their capabilities.
There is a need among creators and owners of digital media for a DRM technology based on a widely used media file format. Where existing DRM technology requires the use of proprietary file formats, and thus of proprietary software (for example, files protected with Apple's FairPlay DRM technology may only be played back using Apple's iTunes software or select Apple-manufactured hardware devices), a DRM technology based on an existing file format can be made to interoperate with existing software—and media production processes built around existing software—when that software is based on a plug-in architecture. Apple's QuickTime Player and QuickTime Pro programs, as well as several other widely-used programs for creating, editing and playing back QuickTime files, fit this description. A need exists for DRM technology built on the QuickTime file format and implemented in plug-ins that extend the functionality of existing programs to provide security against IP theft while allowing creators and viewers of digital media to continue using the same software and processes they are used to.