Hi Jim, The ability to designate an MP3 track as an audio book and have the last played position remembered is a feature that was added to iTunes later than the support for bookmarks in AAC encoded files. Functionally, the reason for using AAC encoding for audiobooks and podcasts is that you'll get better audio quality compared to a similarly sized MP3 encoded file. So the reason that Apple standardized on using AAC encoding is that, back when iTunes started, and devices were more limited in capacity, you could get better sound quality in highly compressed versions of AAC files than MP3 files. This distinction applies at the compression rates that were used for podcasting (64 kbps) or audio books (usually 96 kbps or below), and even the early music files (128 kbps for the stereo music sold in the early iTunes Store). But if you rip to MP3 music files at high bit rates, like 320 kbps, were you're doing less compression, the difference in sound quality is not very noticeable.
So if file size of audio books is an issue, and you use high compression rates for creating the files, your .m4b files will sound better than the comparable mp3 files, but the gain in sound quality will not be noticeable at higher bit rates. In addition, because Apple standardized on .m4b for audio books, this format has the capability of using chapter markers to let you navigate within a single audio book file, as with the audio book files from Audible.com. You have to use software that can generate chapter markers, such the tools Apple supplies for making podcasts, but this is what Splasm does with its AudioBook Builder software. Other than sound quality issues, it's a question of convenience whether you want your audio books as .MP3 or .M4B files. If you use a lot of non-Apple devices, such as an MP3 player or a Loadstone device to listen to your audio books, it will simply be more convenient to keep them as MP3 files so you can play them on all your devices. If you're only using your iPhone or iPod Touch to listen to your audio books, then the convenience of being able to store them as single files with chapter marker navigation (if you use Splasm's software or similar freeware software to build the books), and the slight gain in sound quality relative to size makes it better to keep your audio books as .M4B files. HTH. Cheers, Esther > > > On Jun 27, 2012, Jim Noseworthy wrote: > >> Hi Folks: >> >> >> >> What is the functional difference between creating an M4B file or >> designating an MP3 file as an "audio book" in iTunes? >> >> <--- Mac Access At Mac Access Dot Net ---> To reply to this post, please address your message to [email protected] You can find an archive of all messages posted to the Mac-Access forum at either the list's own dedicated web archive: <http://mail.tft-bbs.co.uk/pipermail/mac-access/index.html> or at the public Mail Archive: <http://www.mail-archive.com/[email protected]/>. Subscribe to the list's RSS feed from: <http://www.mail-archive.com/[email protected]/maillist.xml> The Mac-Access mailing list is guaranteed malware, spyware, Trojan, virus and worm-free! Please remember to update your membership options periodically by visiting the list website at: <http://mail.tft-bbs.co.uk/mailman/listinfo/mac-access/options/>
