Channel Issues & Questions

Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
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2ka
Level 9

Re: I think I may have this mystery solved

Sorry, to be clear, this post was in reference to my earlier assertion that you only had to delete the video transfer characteristics field from the color info to avoid the bug.  I no longer believe that.  Deleting the video transfer characteristics certainly helps, but you really do need to delete all the color information and the color mastering meta info to completely avoid the problem.

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2ka
Level 9

Re: I think I may have this mystery solved

Earlier, ftballpack said:

"Unfortunately Rokus do not play multichannel AAC audio properly, so Plex, Emby, and Jellyfin all transcode the audio to AC3 and remux the video. FFmpeg and the FFmpeg-based Plex transcoders in these products remux the HEVC video and newly transcoded AC3 audio into an MKV with color space info in the header. This is why HEVC MP4s with multichannel AAC can even trigger the transcoding issue that only applies to MKV files, because Plex, Emby, and Jellyfin remux the MP4s with incompatible audio to MKVs with compatible audio and in the process insert MKV header info which causes the display issues."

This is all perfectly true.  I have been having pretty good luck avoiding transcoding (and the bug) -- at least with Plex -- like this:

1.  Use an MKV container.  An MP4 could also work, depending on your need for subtitles, etc.

2.  Make sure the file contains an AC3 audio track

3.  Make sure Direct Play is enabled in the client app.

If you turn on subtitles that need to be burned or cause transcoding to a lower bitrate, it is quite true that Plex will put the color info back in the header.  But at least as of today, that always happens using the H.264 codec at 1080P or below, so the color distortion problem never happens.

TK0
Level 8

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

I had the same problem with my new Roku Express 4K+. I returned it and got a Roku Express for $29 and it does NOT have the color distortion problem. It only gets 1080p and no HDR but at least I can watch my PLEX movies, I can't believe Roku hasn't fixed this problem yet, I doubt they ever will...

mfaller
Level 7

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

Please fix this Roku!!

McDan
Level 7

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

I've found a workaround that is working great for me.

I just use MCEBuddy to process any new files and have it convert to MP4 unprocessed.  It is very quick because it does not have to re-encode the video and the MP4 container does not have the problem.  

I'm finally free of the red **bleep**! 

no1jam
Level 8

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

So McDan, are those h264 files? Or just repackaged raw video and very large?

This problem is with h265 / hevc files only.

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2ka
Level 9

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

What McDan suggests works great in most situations.  This is because MP4 containers don't have a header with color space and color mastering info that triggers the bug, like MKV containers do.

But there is still a situation that causes the bug to reappear:  if Plex decides to remultiplex the file for any reason, it will put it back in an MKV container and add the color info back into the header!  I've seen this most commonly when Plex thinks the audio is incompatible with your player.  The main culprit is multichannel AAC, which isn't supported on Roku.  Plex will transcode multichannel AAC to AC3, and then remultiplex it to an MKC container (with color space info!), which triggers the bug.  It is for this reason that I think it is important for to use the most commonly supported format for multichannel audio, which is AC3, this avoiding the transcode process.  See my post from three weeks ago in this thread for more info.

Reasons other than incompatible audio that cause Plex to remux generally don't trigger the bug.  For example, when burning subtitles, Plex re-encodes using the H.264 codec.  Even though it uses an MKV container, no bug.

You don't have to use MP4 though.  You can simply use a tool like MKVToolNix to remove color and color mastering info from the MKV header.  As long as Plex can direct play the file and doesn't remux it, you will avoid the bug.

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no1jam
Level 8

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

Understood.

I only have this problem on a 2021 4800X, I just turn on subs for that setup and problem solved.

 

Probably try out a shield when I stop buying so much content 😉

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Bacon
Level 12

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

Yep, still broken on OS 11. 

TK0
Level 8

Re: Severe color/contrast distortion while Plex-streaming HEVC+EAC3 videos.

I don't think that PLEX or EMBY are popular or common enough on ROKU, so they don't care to fix this problem.

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