There is only one file type that uses the .TVVI extension:
TitanTV Television Listing File
File format created for TitanTV, a service that provides television listings over the Web; contains data for one or more television programs, including station, channel, program title, program description, episode title, start date and time, end date and time, duration, and media destination.
TVVI files are used by subscribing television programs and PVR devices to display in-progress television listings. Future television listings are stored with the .TVPI extension. TVVI files are saved in XML format.
Updated: February 17, 2015