As explained in Player Assignment to File Types, INTERACT uses different player engines when the Windows Player is selected.
But even the default INTERACT Player extracts some important information from this dialog:
▪Click General - Program - Settings 
.
▪Switch to the File Extensions tab:
Known File Types
All extensions entered into the Video field, are considered to be known video types and will be listed in the file open dialog of INTERACT.
Those extensions are used by INTERACT on both MacOS and Windows, but some formats are unknown to macOS and others are unknown on Windows.
Add a new Extension
If you can play your multimedia file(s) in another common Player, there is a good chance INTERACT can handle that video too. The reason for not being recognized as a valid media file may be a missing extension:
▪Enter a semicolon [;] and the extension you want to add into the Video text field (Like this *.nxt).
Recalc Duration*
Especially MTS and M2TS videos do not provide reliable duration information in their properties, which results in unexpected, irregular behavior in INTERACT.
For video types listed in this field, duration is recalculated on open by the INTERACT Player, resulting in accurate controlling.
Note: Depending on your access rights, you might need to restart INTERACT before your changes are applied.
*) Only available for the Windows-based version of INTERACT