Apple touts its Mastered for iTunes tracks on the iTunes Store as “Music as the artist and sound engineer intended.” Mastered for iTunes tracks are therefore supposed to sound better than tracks you rip from CDs. The basic goal of Mastered for iTunes is to provide a direct downsampling of music from 24-bit, 96 kHz files to 256 kbps AAC files, rather than having a first downsampling to the CD format (16-bit, 44.1 kHz), then another conversion to AAC.
Whether or not the difference is audible is debatable; at a minimum, the conversion from higher quality masters can be seen as producing fewer “rounding errors,” though it’s a bit more complicated than that. Also, the Mastered for iTunes process requires that record labels make some slight changes to their files, notably to avoid clipping, but it allows them to create different masters for the iTunes Store than for CDs, if they so desire. (Yet as you’ll see below, I found much more clipping on certain Mastered for iTunes files than CD rips or older purchased files.)
I was wondering what link exists between Mastered for iTunes files and iTunes Match. If you rip a CD, and match it, will you get Mastered for iTunes files, which are currently sold on the iTunes Store (if available), or will you get equivalents of the CD’s ripped files? Since Apple says there’s a difference between the two, how do they handle this?
When you purchase a Mastered for iTunes file, there’s information in the file telling you this. You can see this by selecting a file, pressing Command-I (on Mac) or Control-I (on Windows, then viewing the Summary tab. The Mastered for iTunes badge below shows you that you have premium files.
If you rip a CD, match it, then download one of the files from the cloud, you don’t ever see the Mastered for iTunes badge. I have a handful of CDs for which only Mastered for iTunes files are available from the iTunes Store (these are new releases where labels only provide files for this format). I added them to my iTunes Match account, matched them, deleted my originals, then downloaded the matched files. I compared them with my original rips (using the methods described below), and saw that these files were not the same; I was clearly getting the Mastered for iTunes files from iTunes Match. But the files don’t display the Mastered for iTunes badge.