I recently upgraded my 2020 Roku Ultra to a 2024 Roku Ultra model. On my 2020 Roku Ultra, I could run the Plex app, connect to my Plex server and play h.264 encoded 4k videos. When I attempt to play back the same videos on my 2024 Roku Ultra, the Plex server tries to transcode the video down to 1080p. If I transcode the video from h.264 to h.265, the Roku Plex client app allows direct play of the 4k stream without transcoding it downward. Did Roku stop support h.264 encoded 4k video? Again the old 2020 Roku Ultra did this without any problems. Direct stream of 4k h.264 encoded video.
