M4A: AAC bounce options in Logic Pro for Mac

When you click M4A: AAC in the Destination area of the Bounce dialog, the following options are available:

• Encoding pop-up menu: Choose Advanced Audio Codec (AAC) or Apple Lossless to set the encoding for your .m4a (commonly referred to as MP4) file. While both encoding algorithms provide high-quality audio, the AAC format uses a higher compression ratio, resulting in smaller file sizes.

  Choosing the M4A: AAC option in the Destination area disables PCM > Surround. Split Stereo is still available.

  If the selected sample rate is higher than 48 kHz, a copy of the bounced PCM file is created (with an automatic sample rate conversion to 48 kHz) before encoding. This conversion takes place because the M4A file type doesn’t support sampling rates higher than 48 kHz.

• Bit Rate pop-up menu: Choose a rate between 16 kbit/s and 320 kbit/s.

  Note: This parameter is only available when the AAC codec is chosen.

• “Encode with variable bit rate (VBR)” checkbox: Variable Bit Rate encoding compresses simpler passages more heavily than passages that are (more) harmonically rich, generally resulting in better quality files.

  Because not all media players can accurately decode VBR-encoded files, this option is off by default. If you know that your target listeners can decode VBR-encoded files, you can turn this option on.

• “Add to Music” checkbox: Check this box if you want to add the .m4a file to your Music library.

  Note: If your Mac is running macOS Mojave or earlier, an “Add to iTunes” checkbox replaces the “Add to Music” checkbox.