You can create an IMF package with Compressor then add other IMF packages called supplemental packages. Supplemental IMF packages reference content from other packages. For example, if you need to add timed text to an IMF package, you can reference video and audio from the main package you created with Compressor, then include the timed text file in the supplemental package.
Supplemental packages can also include, additional video and audio content, additional composition playlists (CPLs), captions, sub scenes and end credits.
You can use third-party apps like MIST from Marquise Technologies and Connect from OWNZONES Entertainment Technologies to create supplemental packages started with Compressor. These apps also include tools for playback and quality assurance of IMF packages, and content mastering.