Metro will not record directly to AAC. Metro always records in AIFF format.
Metro will export MP4's in AAC format.
1. Select the track with the audio that you want to export.
2. Select file:export-track.
3. Click Export-using-quiicktime.
4. Select the Movie-To-MPeg4 from the popup. Click options... to specify specific MPeg 4 settings.
5. Click Save.
Yes. You basically have two options. The best option is to simply save your document before recording. This sets the default location for storing audio files.
The other option only applies if you have not loaded or saved a document since starting Metro. In this case when you press record Metro will ask you to specify the location.