To solve Plex not transcoding 4K HEVC to 1080P H.264 MP4 problems, you can either upgrade your GPU hardware to higher that supports decode/encode 4K HEVC/H.265 (cost too much and waste time), or use some third party 4K HEVC video converter like Brorsoft Video Converter Ultimate (Windows /Mac) to transcode/convert 4K HEVC videos to 1080p H.264 MP4/MKV without extreme CPU usage.
In addtition, you can also use this professional app to rip and backup Blu-ray, DVD contents and common videos like AVI, ISO, MP4, MOV, WMV, etc for Plex Media Server. Thanks to the built-in video editor, you can personalize and retouch your videos in clicks.
Free download the best 4K HEVC Video Converter for Plex:
Step-by-step to Convert 4K HEVC to 1080P H.264 MP4 for PlexStep 1. Load 4K HEVC
Install and launch the best 4K HEVC Video Converter for Plex, simply click Load File to load your 4K HEVC videos to the program.
Step 2. Choose Output Format
Click Format drop-down menu, and pick up H.264 MP4 format from Common Video or HD Videocategory for Plex. MKV is also a good choice, as a container format it takes whatever you give it.
Tip: Simply click Settings bar and you can tweak the settings to meet your needs.Step 3. Start Transcoding 4K HEVC
With above settings, hit the Convert button to transcode and convert 4K HEVC to Plex Media Server compatible H.264 videos. When the conversion is complete, click Open to quickly find the converted movies. Then, Plex will recognize, catalog, play and stream them just fine.