OTA Recordings without transcoding to Roku

I just recently setup OTA recordings and noticed when playing them back through the Roku that we encounter buffering. Some research later, I discovered that Roku doesn’t support mpeg2 and it is causing the videos to be transcoded. My HDHomeRun does not support transcoding.

I have been attempting to test different optimized copies of the recordings, but so far have not found one that will play on the roku without the server transcoding. What is the best way for me to get these recordings to a format the roku will like?