The CXN100 does support the MPEG-4 format.
To provide a bit more detail, MPEG-4 is a collection of standards for multimedia formats, and the MP4 file format serves as a container for both audio and video. Specifically, files with the .m4a extension typically indicate an MPEG-4 file containing only audio. While various audio codecs can be utilised within a MPEG-4 file, the most common is the AAC codec. We're happy to confirm that our Stream Magic platform supports MPEG-4 files with an .m4a extension that contain AAC encoded audio.