Here is a step-by-step guide to how I recently converted a group of mp3s into an audio book (Windows instructions):
- Merge the mp3 files into one.
There are a few programs out there that can help you to merge mp3 files into one, I have tried a lot of them. There is even a suggestion that you can use a windows "copy /b" command to create one mp3 file out of a group of them. I tried that method and while it does work for the most part, the file that results doesn't work in the next step. There is a freeware program called mp3merger that you can get here. It worked quickly and did a great job merging the mp3s so that you can go on to step 2.
- Import into iTunes.
The next step is to import your newly merged mp3 file into iTunes. Depending on your settings an import can do nothing but list the mp3 in your music library, or if you have iTunes managing your music it will actually copy the mp3 file into your iTunes music folder. If it has to copy it and your mp3 file is large like some of the books I created then this can take a few minutes. Here is how you import the mp3 file into the iTunes library:
Start iTunes || File || Import || Find your mp3 file || OK
- Change iTunes "Import" Preferences.
This next step is very important to keep the size of your audiobook down and increase your chances of having your iPod use your audiobook correctly (some of my attempts previously resulted in audiobooks that only played half way). Some information I have read as I researched how to do this suggested that you shouldn't have an audiobook that is more than 350 MB in size. I haven't played around with it enough to know if that is actually a problem or not. Regardless of a potential issue there you don't want your audiobook eating up any more space on your iPod (especially a 4GB nano) than it needs too. The way to limit the size of your audiobook is to lower the bitrate of the file. A standard "high quality" bitrate for mp3s is usually 128 kbps. For music you want the file encoded at this rate or even higher, especially if you are going to play the music on big speakers. But for an audiobook this is not desirable. Most commercial audiobooks top out with a bitrate of 64 kbps, which results in files about half the size. Perhaps it is me (I can't tell the difference between 128 kbps and 96 kbps on an mp3 file) but I think audiobooks sound just fine all the way down to 48 kbps, and you save a lot of space. In one of my recent conversions a 1.1GB mp3 (merged) encoded at 128 kbps ended up being only 392 after I converted it to an audiobook.
So, with the explanation of why to do this out of the way, here is how you change the setting (you may want to notice what your preferences were before changing them so that you can get back:
Start iTunes || Edit || Preferences || Advanced tab || Importing subtab || Import Using: AAC Encoder || Setting: Custom || Stereo Bit Rate: 48 kbps || Sample Rate: Auto || Channels: Auto || Do not check Use VBR || Check Optimize for voice || OK || Uncheck Play songs while importing || OK
- Convert mp3 to AAC.
Now for the part that is going to take the most time, we need to convert the mp3 file into an AAC file. When the file is converted the settings you just changed in step 3 will make the AAC file be encoded at 48 kbps. Here is how you convert the mp3 to AAC:
Start iTunes || Go to your Music library (Music in the left) || Search and find your mp3 (I usually do it by name) || Right click on the "song" || Convert select to AAC
The status of the conversion process will show at the top of iTunes and you'll have a new "Converting..." item on the left. If this process only goes for a few minutes and stops, then you have likely done something wrong with the mp3 merging (this is the problem I had when I used the DOS "copy /b" command to merge my files). If your merged mp3 file is large this is going to take a while. For the 1.1 GB file it took about 40 minutes on my dual core Centrino laptop (converted at a rate of 27.2x).
- Make AAC an audiobook.
This will be the easiest part of the process. The only difference between a song and an audiobook is the extension on the file. The extension of a song encoded in AAC format is .m4a and the extension for an audiobook is .m4b. All you have to do know to make iTunes know you want this file to be used as an audiobook is change the extension. Here is how to do it:
Start iTunes || Locate your AAC encoded file of the audiobook in your music library || Right click || Show in Windows Explorer || Right click on your file in Windows Explorer || Rename || Put ".m4b" on the end || Enter || Back in iTunes delete the song that is listed in music || Import the file that now has the .m4b extension and it will now show up as an audiobook in iTunes.