There is only one file type that uses the .NTP extension:
Natron Project File
Project created by Natron, a node-based compositor used to create visual effects for film and television; contains project data, which includes nodes, output format, number of views, frame rate, and other project settings.
NOTE: Natron revolves around the use of nodes rather than layers for creating visual effects. Node-based compositing features a node-graph, which allows you to see all the effects added to a video.
Updated: July 31, 2015