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Digital Bookmark Mods

by Matthew Russell

If you're anything like me, you own your fair share of digital audio, whether it's from the iTunes Music Store, ripped CDs, podcast downloads, or your own audio notes. And if you're anything like everyone else in the world, you probably spend a lot more time listening to it than organizing and modding it. Well, that might just change after delving into the world of digital bookmarks. In this article, I'll show you how to add better bookmarks to your audio books, add slideshows to your music files, create enhanced podcasts, and share your favorite mods with others--even if they're on protected audio. Interested? Let's get started.


Unless you have a totally amazing memory, you probably use bookmarks more than you realize. Keeping track of important web pages, remembering where you left off in the book you're reading, and dog-earing the coolest projects in the latest issue of MAKE are a few examples that come to mind. But with the latest wave of podcasting ushering in a whole new generation of digital audio, bookmarks are becoming just as important in that arena as well.

For example, consider audio books. Your typical iTMS audio book download comes in approximately two-hour segments that are each pre-bookmarked into hour-long halves. This setup is convenient for burning to CD, since most CDs are around an hour long, but it's not really convenient for anything else--including listening to or navigating through the track in any efficient manner.

A two-hour-long unbookmarked audio book

A nice two-hour-long audio book inconveniently bookmarked into two unmeaningful "chapters"

Rather, it would be much more convenient to have the book broken up into tracks that correspond to the actual chapter or section breaks in the printed book itself. Or you might prefer to have the audio book split into three-minute sections because you like to take notes and want to be able to easily review any given portion of the audio book, and that brings me to my next point: bookmarks are all about you--not someone else who's already decided what's convenient for you beforehand. Let's take a look at how bookmarking can put an end to this mess once and for all.

Apple's ChapterTool

Apple has made available a goodie (still in beta status as of this writing) called the ChapterTool. Download this disk image containing ChapterTool and place the enclosed folder somewhere convenient like your Applications folder. Once you've done that, copy the actual ChapterTool executable to a location in your path, such as /usr/bin/.

Now, go ahead and verify that ChapterTool is in your path by getting back a meaningful response with which ChapterTool in Terminal. Assuming everything checks out, go back and double-click on the audio file sample.m4a that's in the enclosed Sample folder to hear the sweet elevator music, courtesy of Cupertino. Note that the album artwork pane is empty.

Next, take a moment to carefully peruse the sample.xml file included with the sample. It's an XML file, but you should be able to understand most of it, even if XML is Greek to you, since it's thoroughly commented. Once you have a good handle on it, take a look at the same XML file without all of the commenting clutter:

<?xml version="1.0" encoding="utf-8"?>
<chapters version="1">
    <chapter starttime="00:00">
        <link href="">My Podcast Homepage</link>

    <chapter starttime="00:08">
        <link href="">My Biography Page</link>

    <chapter starttime="00:15">
        <title>This is the End</title>

    <chapter starttime="00:20">
        <title>No, Really.</title>

Pretty simple, right? It specifies four different chapters, where each chapter has a title and, optionally, contains an image and a link.

Let's use the ChapterTool to add apply those edits contained in the XML file to the elevator-music sample track so you can see how easy it is to add bookmarks, pictures, and links to songs. Navigate to the ChapterTool/Samples folder in Terminal and type the following:

ChapterTool -x sample.xml -a sample.m4a -o output.m4a

Here, you're invoking ChapterTool and telling it to apply the edits in the sample.xml for the sample.m4a track and to produce the output.m4a track as a result. That's about all there is to it, but you can turn to ChapterTool/About Chapter Tool.rtf for more information.

To view the changes to the track, double-click output.m4a and it should automatically open and run in iTunes. In addition to the nice elevator music you heard before, you should see some images and hyperlinks in the artwork folder. Also note that the bookmarks button in iTunes contains thumbnails of your embedded images, and that if you were to burn the track to disk, it would split into tracks designated by the bookmarks.

Apple's sample bookmarkedA close look at the album artwork pane

Apple's sample after you modify it to have bookmarks with optional images and/or links

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