Plex Media Player on embedded platforms currently has no way of knowing whether or not x265 playback will be smooth or not.
It would be great to have a new setting that will tell the server to choose a x264 alternate file to direct play or to transcode to x264 rather than direct playing a x265 file that the end-user knows will play choppy. This would be similar to the settings for supported audio codecs.
2022 clean-up: obsolete (PMP is no longer officially supported; please use Plex for Windows/Mac/Linux or Plex HTPC instead – Plex HTPC allows individual mpc configurations and overrides)