There is only one file type that uses the .JTS extension:
Cyberlink AVCHD Video File
High-definition video file downloaded from a JVC HD camcorder and edited with Cyberlink video-editing software; contains video data stored in an MPEG-4 AVCHD format; used to preserve high-definition video from the camcorder.
JTS files can be converted to more common video file types using Cyberlink software, such as .AVI and .MP4 files.
NOTE: Cyberlink video software is sometimes included with JVC digital camcorder purchases.
Updated: November 18, 2012