Split m4a into stems

Download and install the latest version of Filestar.
Right click on one or more M4a file(s) on your desktop and select Convert with Filestar.
Type split into stems in the search box.
Press Split.

What is .m4a?

Name: MPEG-4 Audio File
Extension: .m4a
Format: Binary
Category: Audio
Developer: Apple
Description: An M4A file is an audio file created in the MPEG-4 format, a multimedia container format used to store compressed audio and video data. It contains audio encoded with either the Advanced Audio Coding (AAC) codec or the Apple Lossless Audio Codec (ALAC).
MIME Type: audio/mp4
Sample: sample.m4a
Wikipedia: .m4a on Wikipedia