I was able to get this done to fit my needs. In case anyone else finds it useful, here is what I did:
1. Enabled NextPVR to export an .xml file with recordings
2. I use VideoRedo and am using VideoRedo-AutoProcessor to watch the NextPVR recording directory. When recordings finish, VideoRedo-AutoProcessor will automatically convert the recordings from .ts to .dvr-ms files
3. I wrote a PowerShell script that does the following:
a. Pulls the XML file created by NextPVR
b. Updates the metadata in the dvr-ms file using the data from the XML file (title, episode, parental rating, tv affiliation, program description, and tags)
c. Removes the original .ts and .xml files that are no longer needed
The only real challenge was getting a command line tool that will edit the metadata. I was able to install the Windows Media Format 11 SDK, which was written for XP. I changed the installer to "XP Compatible" and was able to install it. Since I only needed MetaDataEdit.exe, I wasn't too worried about compatibility. Again, this fits my needs since 100% of my viewing is done through WMC on XBOX 360s.
Seems like it would be a lot easier to just record with WMC, which is likely what you were doing for the last 4 years? Did you upgrade to Windows 10 or just can't currently get WMC guide data?