

Plex is working to improve 4K playback on the Fire TV, so look for better support with future updates.

Thirdly, even if your 4K files fits all the criteria, it still may not play directly due to a bug identified last week. Secondly, the Plex app for Amazon Fire TV 2 doesn't offer support for surround sound, and the audio files must have an AC3 or AAC audio track present. First, the 4K files must be encoded with a maximum bit depth of 8-bits per sample and contain metadata identifying them as having a Main Profile level. The fact is that many users finding 4K files don't meet the required specifications for direct playback by Plex. Can Plex on Fire TV 2 perfectly handle all 4K video? This includes support for H265 HEVC encoded files.

This means 4K videos can be directly played on the Fire TV without your Plex server needing to transcode the files. Good news: Plex had added official support for the 4K video files on the 2nd generation Amazon Fire TV with their v4.21.0.528 update. Plex adds support for 4K playback on Amazon Fire TV 2
