Metadata - Minimum Data Elements?

What are the minimum data elements for a TiVo Metadata file?

I want to simply organize random Video Podcasts pushed via pyTivo under a couple simple folders, no descriptions, etc., are needed.

From the below list, I think I only need:

title : <program title>
seriesTitle : Webcasts
episodeTitle : <program title>
time :
seriesId : <arbitrary number>
description :
isEpisode : False
originalAirDate : <today>
isEpisodic : False

Can I omit the unused elements, or do I need to send NULLS?

Thanks!