Event Monitoring Variables - Request audio file length

While there are many useful variables associated with the event monitoring functionality including File Path, File Size, etc., we have a use case that would make "Length" very handy. We use use Cerberus for many things but one is for retrieving call recordings for our call center and we use the file transfer event monitor to build a table associated with a particular call recording file. Having the length of the audio file captured from the file properties and included as a variable would be awesome.