You are misunderstanding the issue and why the color issue applies even to HEVC files in MP4 containers. The reason why direct play multichannel AAC audio is an issue was previously mentioned in this thread. Roku Ultra 2020, aka 4800x, direct play, colors distorted when playing back HEVC, 1080p content on 1080p screen. Applies to both 8-bit and 10-bit packaging of 8-bit content - #25 by boblinthewild
Roku has a known issue with multichannel AAC audio which causes Rokus to play the audio back as dual-channel. To work around this issue the plex server converts the multichannel AAC audio to AC3 and outputs the multichannel audio in a new MKV container that contains the color elements, introducing the HEVC/distorted color issue.
Yes, you can “force” the Roku client to direct play AAC audio, but it will output the audio as dual-channel. Dual-channel audio is fine if you plan on playing the audio back on your TV, but if you have a surround sound system, it will completely destroy the surround sound effect.
No one is debating whether it is possible to force the plex client to direct play AAC audio. The question is do you want to convert multichannel audio to dual-channel audio and have that dual-channel audio sent to your surround sound system? At that point, are you not better off forcing the client to transcode everything, so that the surround sound works properly? Why would my brother want a dual-channel down-conversion sent to his 9.1 channel Atmos home theatre?
