Using Mac OS X’s powerful built-in media encoding tools, large AIFF audio files can be quickly and easily converted to compressed high quality M4A audio, ready for use on in iTunes or an iPod, iPhone, or elsewhere.
No additional downloads or software is required, the media encoding tools are free and bundled in Mac OS X since Lion. They should be available by default, but you can enable the media encoders if they aren’t visible in contextual menus for you.
How to Enable the Video & Audio Encoder Tools in Mac OS X Lion?
- Launch System Preferences from the Apple menu
- Click on “Keyboard” and then click on the “Keyboard Shortcuts” tab
- Select “Services” from the left, and scroll on the right for “Encode Selected Audio Files” and “Encode Selected Video Files”
- Check the box next to both of those options and close out of System Preferences
- Confirm encoding tools are now enabled by right-clicking on an audio or video file and looking for the Encode option

Convert AIFF to M4A Easily from Mac OS X
- Right-click the AIFF audio file and choose “Encode Selected Audio File”
- At the “Encode to MPEG Audio” window, pull down the Encoder menu and choose “iTunes Plus”, this will result in a 256kbps m4a file
- Change Destination if necessary, otherwise click on “Continue” and let the encoder do its work
- Look for the newly converted m4a file in the same directory as the origin AIF

How long the conversion process takes depends entirely on the processing power of the Mac, but it’s always quick. Other than greater compatibility and portability, the other benefit of encoding audio is file size reduction.
If you want to convert M4A to MP3 on Mac, please follow this guide: How to convert M4A to MP3 on Mac?
Source from osxdaily.com














