This Mac tip is provided by Mark Greentree and was originally posted on Mark’s blog – Everyday Mac Support. For more of Mark’s tips visit his site, follow him on Twitter, or browse his archive of posts here.
Knowledge of useable iTunes audio formats can help users achieve the best possible mixture of sound quality vs file size vs ability to replay content.
Users who will find this article most useful would be anyone who imports music from CD’s they own or convert music from one format to another.
The formats which iTunes can read and hence encode are: AAC, AIFF, Apple Lossless, MP3 and WAV.
Let’s take a further look at these formats and their functions:
AAC: Advanced Audio Coding is a lossy compression and encoding format for digital audio which was designed to be the successor of the MP3 format. ACC’s advantage over MP3 is a higher sound quality at the same bit rates. As a standardised format a user is able to use this format with the knowledge that many of the popular digital music players are compatible with the technology.
AIFF: Audio Interchange File Format is a non-compressed, lossless format which is most commonly used on Apple Macintosh Computers. As a result it is less supported on portable media devices than other options and it also produces a higher file size.
Apple Lossless: This audio codec was developed by Apple. It is a lossless music format with file compression. This means that files are compressed approximately between 40% and 60% original file size with no degradation in quality. It is also specifically engineered to be used with battery powered devices such as iPods as the decompression performs much quicker than other alternatives therefore preserving battery life.
MP3: This is the most common digital music codec available. However, it is a lossy codec being up to 11 times smaller on average than the original source file. In order to get the small file size music is essentially erased. In this erasing technique the codec will remove what it believes is not within the range of human hearing. Be that as it may, if you listen to an MP3 encoded at 128 kbit/s and then the original on a CD for example you will immediately notice the difference.
WAV: Waveform Audio File Format is a standard for Windows platforms. As a result it is less supported on portable media devices than other options and it also produces a higher file size.The format is quite flexible allowing uncompressed WAV sound files to be produced. Compression is also available to this format.
In my opinion I would stick with MP3. Whilst, the audio quality of MP3 at lower bit rates isn’t as good as other options you can change the bit rate setting in iTunes allowing you to use up to 320 kbp/s by using the custom settings. The quality output at this level is certainly more than adequate for everyone besides audiophiles. The MP3 format is the most widely support and popular codec and I don’t see this changing for a very very long time.
You can change your importing settings in iTunes by going to the preferences window then the general tab and then click on Import Settings. Each codec will give you a series of preset options and generally the ability to customise your own specific settings.