If you want to direct play 4K video on LG Smart TV with WebOS 3 using the Plex, your 4K videos must be H.264 or H.265 encoder in MP4 container, otherwise, the 4K videos will be transcoded to 1080P. This video show a 4K video converter software to transcode all the 4K videos to mp4 with H.264 or HEVC codec 4K video for Plex direct playback on LG TV with WebOS 3.0/2.0.
Official Guide(More details here): http://www.multipelife.com/direct-play-4k-on-lg-tv-with-web-os-3-using-plex.html
Pavtube Video Converter Ultimate: http://www.multipelife.com/video-converter-ultimate
Pavtube iMedia Converter for Mac: http://www.multipelife.com/imedia-converter-mac
Still wanna to know more tips about video playback or editing? Please feel free to Email Us: support@pavtube.com