User guide

634 Chapter 27 Bouncing Your Project
M4A: AAC Format Options
Choose the M4A: AAC name (and activate the checkbox) in the Destination field to
access the following options:
Encoding
Choose Advanced Audio Codec (AAC) or Apple Lossless to determine how your .m4a
(commonly referred to as MP4) file will be encoded. Both encoding algorithms provide
high quality audio, with the AAC format using a higher compression ratio, resulting in
smaller file sizes.
Bit Rate
You can choose a rate between 16 kbps and 320 kbps.
Note: This parameter is only available when the AAC Codec is chosen.
Encode With Variable Bit Rate (VBR)
Variable Bit Rate encoding compresses simpler passages more heavily than passages
that are (more) harmonically rich, generally resulting in better quality files.
Unfortunately, not all media players can accurately decode VBR-encoded files, which is
why this option is turned off by default. If you know that your target listeners can
decode VBR-encoded files, you can switch this option on.
Note: This parameter is only available when the AAC Codec is chosen.
Add to iTunes Library
The Add to iTunes library option adds the encoded file to the iTunes library.
Should the selected sample rate be 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: AAC format does not support sampling rates
higher than 48 kHz.