HDHomeRun .ts DVR file transcoding

[mrplow]

I have a TS-251+ with Plex LiveTV+DVR and an HDHomeRun Extend for ota. On the TV side I have a Roku Ultra. When I record ota shows in Plex they are saved as a .ts file on the nas and playback on the Roku takes ~1 min to load. After the load time completes they play fine so I'm mainly trying to cut down on that initial load. Checking the status in Plex while watching a recording it says "Video Transcoding H264 to H264" and "Audio Transcoding AC3 to AAC". I've tried manually transcoding the files in the QNAP web interface but it fails with "File read/write error". Is there some way I can convert those .ts files to the H264/AAC format that Plex and my Roku seem to want? Hoping to add that as a postprocessing script in the Plex dvr settings.