“Reference” means these are not self-encoded Files. Reference files are sort of a container for the “original” media files. Open a reference file in QT player, press cmd-j, click on the “Ressources”-Tab. Now you’ll see all the associated files. Therefore the codec listed by a mediaplayer like QT Player is not the codec of the reference file but the codec of the (first?) associated file.
Given that M100 can mix different codecs, reference files generated by M100 can also contain different codecs. If you want a file with a specific codec:
1. use only one codec for capturing and rendering. And export “by-reference”
or
2. choose a codec of your choice in M100-codec-settings and export “self-contained”