AAC/MP4 import

These options set the sample size and downmix options for imported AAC/MP4 audio. The AAC decoder can output 16-bit, 24-bit or 32-bit PCM. For better quality, select a bigger sample size. The "Downmix to stereo" option determines how surround files are handled: if it's checked, files with more than two channels are downmixed to stereo, otherwise they're imported as surround.