Q: For a while now I have been trying to figure out how to locate all of the MP3 formatted songs in my iTunes library and convert them to AAC. This becomes increasingly difficult when your iTunes is over 50 GB and the only way I have is to use the search feature in Finder to see a list then go back into iTunes and search again then convert. This takes forever as you might imagine. Is there a better way to do this?

– Kyle

A: There are definitely much easier ways to do this; you can create a Smart Playlist to gather all of your MP3 files in one place and then view and convert them from there or simply display the “Kind” column in your main iTunes library by going to your View Options and then sort by that column to group all of your MP3 tracks together.

Ideally, if you have a lot of tracks you’re planning to convert, a Smart Playlist is the easiest option. A Smart Playlist is basically a saved search of your iTunes library that will always display tracks based on selected criteria. You can therefore easily tell it to only include MP3 tracks and it will remain updated to only display those tracks in your library that are in MP3 format.

To create a new Smart Playlist, simply choose New Smart Playlist from the File menu in iTunes, and a dialog box will appear asking you to specify the criteria for your Smart Playlist. Set “Kind” to “MPEG Audio” and the Smart Playlist will only include your MP3 files.

You can also specify additional criteria if you want to narrow the list down further, such as ensuring you include only Music tracks, or filtering your list to a certain bit rate only.

There are a couple of things to keep in mind about converting your tracks to AAC. Firstly, be aware that iTunes makes a copy of any converted tracks rather than overwriting the original track. This means that the MP3 file will still remain in your Smart Playlist and a new, duplicate track will be created in AAC format. You’ll have to manually delete each MP3 track yourself once you’re satisfied with the conversion; you can do this directly from a Smart Playlist by holding down the SHIFT key (Windows) or OPT key (Mac) while hitting the delete button.

More importantly, however, you may want to consider the issue of quality loss from converting between lossy formats. Converting an MP3 file to AAC will result in a quality loss, as you’re effectively getting the combination of two different lossy encoders. This may not be a huge issue if you’re dealing with high-quality source MP3 files (ie, 256kbps or higher) and going to a lower bit-rate AAC format, but there will still be a quality loss. You will always be far better off to re-rip the tracks as AAC from their original source CDs if you have them, and as an added advantage, iTunes can actually replace reimported tracks for you, saving you the trouble of having to cleanup duplicate tracks. In this case, the MP3 Smart Playlist can still be a useful way of identifying those tracks that you want to re-rip from CD, and the tracks will actually be removed from the Smart Playlist as you re-rip them in AAC format.