The Fabulous Bookmarkable Matrix

What's A Bookmarkable Track?

A bookmarkable track is one that has the ability to begin playing from the point at which it was last paused or stopped.

Some History

The "bookmarkable" feature was introduced by Audible.com for its audiobook downloads and co-opted for iTunes by Apple in late 2003 or early 2004. As far as I can remember, Audiobooks downloaded from Audible.com had the bookmarkable feature which iTunes could take advantage of around then, which would mean that iTunes version 4.1 or 4.2 was when bookmarkability was introduced.

The Infamous Apple Knowledge Base Article 93731 appeared around then and mysteriously disappeared about two days later. The IAKBA essentially said that a third-party application would be able to change any plain AAC file to bookmarkable simply by changing that file's file type to "MFB ". So, I wrote "Make Bookmarkable" and there it is. Changing a file's file type by AppleScript has been possible since System 7! Legend has it that Audible baulked about Apple making the Secret Bookmarkable Formula publicly available, and thus the K-Base article was pulled.

But all that fuss is fuel under the reactor now, Mr. Time, now that the cat's out of the bag.

The first mention of bookmarking and the "Make Bookmarkable" script on this site was on March 1, 2004. I didn't pay a lot of attention to things like that because I was not an Audible subscriber (prefering to read books the Old Fashioned Way). But when it was suggested that file types could be altered by a third party application I just jumped at it.

Eventually, Apple provided the iPod an "Audiobooks" category, into which audio files of the "M4B " file type and Audible ".aa" files would be displayed. Although the Genre of downloaded audiobooks from Audible was "Audiobook", this didn't make any difference. Only "M4B " file types or Audible ".aa" files showed up in the iPod's Audiobook category.

This confused a lot of Mac users.

Windows users are able to change an AAC file's extension to ".m4b" and make the file bookmarkable. Apple users can't do this because the Mac OS doesn't give much creedence to the extension of a file, unless the file has no file type. In this case, the Mac OS has to rely on the extension to identify the file's file type. So, setting an AAC's file type to "    " (four spaces) and changing the extension to .m4b will make an AAC file bookmarkable.

Even so, it was generally recommended (by many authoritative sites) to use the "Make Bookmarkable" AppleScript to change plain AAC files to the bookmarkable type to Get The Bookmark Advantage. But the "Make Bookmarkable" script only changed the file type and not the extension; yet the "kind" of the track would then be displayed in iTunes as "Protected AAC Audio File". Users inundated me with the query "Are my files now protected?!". No. You can't change the protected status of a file. iTunes just "sees" files of the "M4B " type that way. It's sort of a GUI thing. (By the way, the latest version of Make Bookmarkable v1.5 does change the file extension to ".m4b" which hopefully will calm some confusion.)

Things got weirder as the iPod and iPod software was updated. Users would rip their audiobook CDs to AAC, use "Make Bookmarkable" to convert the imported files to "bookmarkable" files, and wonder why their now-bookmarked files were or weren't showing up in their iPod's "Audiobooks" and/or Music categories.

The Fabulous Bookmarkable Matrix

Below I have created a table (yes, a real HTML TABLE) that graphs how various "bookmarkable" tracks/files will be displayed by your iPod. This is for Mac users. Windows users are on your own. I am not an expert, findings are based on my own experiments, only as a guide, etc.

I tested files on a first generation 5GB iPod and a first generation 4GB iPod Mini; that is, a non-click-wheel and a click-wheel type iPod, respectively. There is a difference. I have the most up-to-date (to date, 12.30.2005) iTunes software, iTunes 6 and iPod Software 1.1.3. I have run several tests, and the matrix below describes how various "bookmarkable" files will or won't appear in iTunes and those iPods. The iPod Shuffle is not listed because it works differently, but you can pretty much rely on the same results.

Note that the "Audiobook" category on an iPod has a unique sort of bookmark feature (like the other Song, Artist, and Album Categories). It remembers the last track played. Regular playlists do not have this feature.

The matrix was originally posted in 2005. I will re-display it when I have updated it.

Addenda:
* Changing the extension from "m4a" to "m4b" is sufficient for Windows users to convert an AAC file to "bookmarkable". For Mac users, unless the file type is also changed from "M4A " to "M4B ", (or the file type is completely blanked out) a file will not be recognized as "bookmarkable".

** Make Bookmarkable will change the file type of each selected AAC track (unprotected; that is, AACs you have ripped or converted to AAC files yourself) to "M4B " and its extension to ".m4b", thus making them bookmarkable.

*** Join Together is a script that will enable you to join the files of selected iTunes tracks together with QuickTime Pro and export them as a single AAC file/track. Optionally, with Apple's ChapterTool application installed, it will create a "chapterized" audio file of the exported AAC file. Joined files can be saved as either the "M4A " or "M4B " file type using, respectively, the ".mf4" or ".m4b" extension.

Links

Here are some sites that I have checked out to provide pieces to the puzzle:

The Complete Guide to iPod Audiobooks

Kirk McElhearn's article at iLounge explains just about everything about using audiobooks with iPod.

Frequently Asked Questions About Audiobooks and iTunes

FAQ with several common questions about bookmarkable files, joining tracks, and so on.

Pocast Chapter Tool

Although primarily a tutorial on creating enhanced AAC files as podcasts, there is a section here explaining the behavior of "m4a" and "m4b" files.

3AM Coffee Software's "iTunes Join"

"iTunes Join" is a set of [shareware] applications that allows you to join (concatenate) multiple tracks into a single new track. Head 3AM'er Derrick Bass has some very good info on joining and "chapterizing" files.

TUAW Tip: The Importance of File Extensions

The Unofficial Apple Weblog has a tip that contains info on the differences between file extensions in Windows and Mac OS's.

Audio File Formats: AAC Follow-up

This Wired blog entry contains info on audio file types.