CEA-2003-C

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CEA/APA Audiobook Logo

The goal of CEA-2003-C is to create a broad, extensible standard for audiobook publishers, audiobook device manufacturers, and audiobook software developers in order to create the best listening experience for the audiobook consumer.

The Consumer Electronic Association and the Audiobook Publishers’ Association combined forces to develop a way to solve the challenges unique to spoken word audio. The first revision of the standard, CEA-2003, addressed physical media and the well-known MP3 codec exclusively. Based on the Optical Storage Technology Association’s (OSTA) MultiAudio specification, CEA-2003 developed an audiobook extension set to further enhance audiobook table of contents and summary information. This binary file enables playback devices to quickly retrieve the table of contents without the time-consuming disc initialization that can occur while the player identifies all the files on a disc.

CEA-2003-C retains backwards compatibility with the binary file format on compressed file discs, but introduces the audiobook extension set to OSTA’s MPV-Music specification. The XML-based specifications further enhance the capabilities of playback devices by enabling exchange and playback of collections of digital audio, photos and videos among various playback devices and media. The CEA-2003-C extension set for audiobooks operates independently as a fast and easy way to enable playback of audiobooks, and can also be combined with the core MPV specifications and other extension sets to create diverse and unique playback experiences.

[edit] Implementation and Enhancement Suggestions for Playback Devices

There are surprisingly few steps necessary to provide a pleasant playback experience for the audiobook consumer. In its simplest form, implementing support for CEA-2003-C is a matter of recognizing the table of contents file exists on the media, reading the time offset markers that reside within the table of contents file, and displaying the level name and point of play.

The basic two-level navigation gives the consumer a choice in display and navigation of the file level or a time offset within the file; typically a chapter (file) and page (60 second audio increment). Displaying the information and allowing navigation from chapter to chapter and/or page to page gives the consumer a point of reference and information on how to resume playback if the media is transferred to a different device. A very simple, low-memory device can effectively navigate these two levels without the need to enumerate and index file information, thereby increasing the speed on startup and when navigating through multiple files and directories.

Although not required to conform to the standards, there are several small enhancements to providing an improved listening experience. When the CEA/APA Audiobook Format is identified by the player, auto-resume feature should be automatically invoked, whether it is a default setting or not. Providing fast forward and fast reverse through a file is very important for an enhanced listening experience. The table of contents file holds additional information regarding the audiobook, such as title, author, total playing time of the audiobook, narrator, etc. A way to easily view this information and catalog multiple playlists based on audiobook information is an enhancement the spoken word audio aficionado relishes.

A “ReRead” feature is especially useful for portable media devices. A phrase or sentence missed due to outside distractions can be easily heard again by a quick button push, which can move the playback point in reverse for a few seconds on each push. Playback then resumes with no other intervention by the listener.

New in CEA-2003-C are two optional additions; the ‘roundtrip bookmark’ feature, which enables the player to save and transfer multiple bookmarks and/or the auto-resume point, and level “unit” and “context” identifiers, which enables playback devices to provide a more customized handling of levels.

The ‘roundtrip bookmark’, or bmark.aub file, is an XML file separate from the table of contents file that is written and read by the playback device. By recording user bookmarks and the auto-resume point in a separate file, this would enable the transfer of such information between Audiobook Compatible devices and locations. An example of this usage would be the consumer listening to an audiobook in their automobile with a portable media device hooked through the car stereo. When the playback is stopped, the portable media device would record the stopping point in the bmark.aub. The portable media device is then synchronized with the consumer’s home entertainment unit, either through a wired or wireless connection, and transmits the bmark.aub with other information. The home entertainment unit would read the information and resume playback at the point the audiobook was stopped previously.

A specialty audio playback device designed for audio versions of a daily newspaper and monthly special editions could make use of the level identifiers and provide more specific playback and display options. For instance, a subscription service that delivers the audio versions of a daily newspaper and periodic “special editions” wirelessly to the Audiobook Compatible player could include category identifiers to the player within the table of contents files. If the category is identified as a Periodical, and the units are identified as Columns, a preset display could be utilized to present the information to the consumer without need to read and display each level’s description individually.

[edit] Implementation and Enhancement Suggestions for Content Providers

Content providers should incorporate the table of contents file generation in their production methods. For audio-only device playback, a simple two-level structure and basic information regarding the spoken audio will be a welcomed and enhanced experience for the consumer. Providing a basic MPV-core file in addition to the MPV-audiobook file will increase the compatibility in the case of an MPV-music-aware player that is not Audiobook Compatible.

For backward compatibility, it is suggested that digital audiobook files are named in alphanumeric order to ensure that even the lowest-memory devices will present the audiobook in the order in which it was intended. If adding metadata to a file, such as an MP3 ID3 tag, fill the Album tag with the title of the book in order to group all files together in the display. If file names or chapter numbering is used, make certain to use alphanumeric naming conventions for file names as well as the Title tag. Don’t forget the leading zeros – otherwise, you may find your audiobook presented and heard in an undesirable order - Chapter 1, Chapter 11, Chapter 12, Chapter 2, Chapter 21, and so on.

Remember that the table of contents file is just that – a navigational structure with some key information regarding the audiobook. Provide a simple, easy to use and understand system of navigating through the audiobook, knowing at which point one stopped listening, and how to get back to that or another one, depending on the content. A fiction novel can be easily presented and understood with simple two-level navigation: Chapter and Page are familiar references to the listener. A periodical or podcast may be best presented with differently named level displays; CEA-2003-C provides the way to communicate the content provider’s method of navigation in a straightforward, understandable and easy-to-implement way.

The technical standards provide ease of use and relatively simple navigation, but can be combined with other extension sets of the MPV specification to create a rich multimedia experience. These extension sets and playlists can be combined to include photo presentation during an audio presentation of a newspaper, for instance, or display the text of a book as the audio is being played. There are a variety of opportunities for enhanced-value, multimedia experiences.