Apple recently inaugurated the “Mastered for iTunes” (MFiT) program, which is both a technical initiative and a marketing initiative. Apple recommends production guidelines to insure that AAC files sold in iTunes’ “Mastered for iTunes” store sound their best.
iTunes sells files in a lossy AAC format. MFiT files and iTunes Plus are Variable Bit Rate (VBR) 256 kbps; other iTunes files are 128 kbps. Digital files are encoded at Apple, from masters supplied by record labels or by aggregators like CD Baby. Typically, labels and aggregators send iTunes CD masters (16 bit/44 kbps resolution).
Though iTunes is not selling high-resolution (24 bit/44 or 24/96) music (yet), Apple now recommends high-res files for iTunes submissions, which will result in better sounding AAC files. MFiT masters are 24 bit files.
Mastering engineers are “certified” by Apple so that Apple accepts masters created in their studios as MFiT. All Airshow mastering engineers are MFiT-certified.
Apple’s MFiT initiative confirms what we have long known – AAC (and MP3) files created from squashed, highly compressed masters don’t sound nearly as good as those made from more dynamic masters. Lossy codecs like AAC and MP3 will overload and distort unless there is sufficient headroom in the source files. And, AAC files made from 24-bit (or 32-bit) source material sound closer to the original than those from 16-bit sources. Airshow uses the Apple MFiT utilities to insure that the music will sound its best as iTunes downloads.
CD Baby is the first aggregator to announce support of high- resolution MFiT files. This is great news for independent artists, whose work can now be delivered to iTunes in an optimized format.
The new “Mastered for iTunes” logo in the iTunes store indicates that the AAC files were made from high-resolution sources that have been optimized for the AAC encoding process. Simply put, this means better sounding iTunes music, even in the lossy AAC audio file format. Be aware that your MFiT release may not end up in the MFiT section of the iTunes store; that’s a marketing decision by Apple. Your iTunes downloads, even if they are not in the MFiT section, will benefit from the higher quality that MFiT affords.
Many Airshow clients already release their music to HDTracks, which sells uncompressed 24-bit FLAC files. A 24-bit master can serve double-duty for these online retail outlets.
When you bring your next project to Airshow, be sure to discuss the digital release plans with your engineer so we can anticipate all of your needs, and incorporate “Mastered For iTunes” into the mastering session workflow.
If you are using an aggregator that accepts MFiT files (like CD Baby), or if your record label is an iTunes Content Provider, we recommend you order a MFiT master in addition to any CD master you need. The MFiT master will be 24-bit at the highest sample rate your project allows (though some labels prefer 44.1k 24-bit for MFiT). We check the master for MFiT compliance using Apple’s utilities and/or the Sonnox Fraunhofer Pro Codec. We audition the master through the Apple AAC encoder and decoder to see how the music will sound on iTunes, and we ensure that the levels will not create any overloads in the AAC encode process.
Apple’s MfiT and iTunes + files are 256k AAC. It’s still not CD quality, but it’s pretty close.
For more:
http://www.apple.com/itunes/mastered-for-itunes/
http://www.sonnoxplugins.com/pub/plugins/products/pro-codec.htm