Thanks for the link!
Unfortunately I'm new to Alfresco and some of the instructions are a bit too vague. For example the instructions will just say "Register that content model through context file" and doesn't really explain how the code should register it. Alfresco's wiki has some examples on this but I don't think it's exactly what I need to do as I'm just adding onto the existing audio content model.
I tried a workaround by simply putting the data into the existing Genre metadata field for the mp4 file. The data shows up in the full properties section, however it is not actually indexed/searchable by Alfresco.
Is there a way to index the Genre metadata field?