What does Mastered For iTunes mean? In this article we explain all about that.
WHAT IS MASTERED FOR ITUNES
Mastered for iTunes is a set of rules (established by Apple) to optimise the mastering process for distribution on the iTunes digital platform. The main objective is for the music to be reproduced as best as possible for the common reproduction system such as earbuds, iPhones, laptops and other consumer products. These rules include:
BIT DEPTH AND SAMPLE RATE COHERENCE
As explained on Apple’s 10 page long Mastered for iTunes specifications document, the bit depth or sample rate of the music should not be changed during the mixing or mastering process. Switching between one format to another is never a good idea, but it’s particularly critical for digital distribution as the music then gets coded into compressed formats such as AAC.
iTunes is doing its part to fight the loudness war and ultimately Apple wants to get music to have a consistent loudness throughout their platform. This means without unpleasant jumps in loudness between one song and another and unwanted distortions. If the masters are too loud, iTunes will take the level down to match with everything else.
AVOID INTERSAMPLE CLIPPING
Even if the level may not hit above 0 dBFS ceiling, the analogue rendition of the music may go beyond the point of audio clipping. This can happen because of the way the level of each sample is averaged to its neighbouring samples to recreate a continuous waveform. Failure to comply with this rule can result in the sound distorting on common consumer’s reproduction system.
iTUNES AND THE FUTURE
Apple is planning on introducing better quality audio files for the iTunes platform at some point in the future and they will probably even expand these rules. So starting to observe the Mastered For iTunes document is a great way to future-proof your music.