If you play video via Plex or Emby and reduce the streaming quality to anything lower then its original quality, or if you add subtitles - Then the video will transcode during playback.
If you run with the 12$ plan, you are allowed 2 concurrent transcode stream - If you attempt to start a 3rd, you will be met with the message "Not enough CPU to start conversion".
If you stream at original (highest) quality, you will be direct playing - You can run any amount of direct play streams on all plans offered by RogueStreamz.
Steps on how to adjust this setting for multiple devices are here: