Converting TS files is a pain in the neck. Typically a raw TS file is anywhere from 2 GB to 10 GB. Turning on transcoding while recording does not help that much. If I use HandBrake to convert the TS file to MKV with Intel QSV, sometimes handbrake stops encoding part way through and keeps running for hours or even days until I intervene. Most of my TV shows I will down scale to 720 P, and a quality factor of 21 for a reasonable storage size.
I finally came up with a fairly efficient way to encode the videos. I set the folder optimize to 4 Mbps 720P video. I then use those optimized files as input to handbrake. That reduces the video to about half the 4 Mbps 720P size, without a noticeable loss of quality. Plus, handbrake is really fast on this conversion. It takes just a couple of minutes for a 30 minute TV show. Much less time than it takes Plex to create the optimized version.
The only problem is Plex use mp4 for the optimized files. But the mp4 format loses the closed captions… It would be great if there was a way to preserve those, as typically downloaded subtitles are out of sync.