Roku Ultra (4800R) oddity with MKV's that are flagged as BT.709

[sjlcjl 5]

New problem for me..  I started processing some 4k UHD stuff and when I squeeze them to BT.709 for remote viewing, I have an issue where the Roku 4800's will show things in a orange/red tone.. I think they are trying to display BT.2020..  If I select playback correction, it looks like it should..  I looked around the MKV file header and if I just flat out remove the BT.709 info from the header (as it should default to BT.709) then it plays fine on the first try..  

For whatever reason, even if the file is just a Blu Ray and I convert it with Handbrake it tosses that info in there to tag it as BT.709 and the Roku 4800 will display it all weird..  (Older Roku's handle the files fine, as does my Android TV, and my Shield Pro)

Hadn't been using Handbrake in the past but need it now as it helps with all of the color space/audio/subtitle conversions for the compressed files a lot better than anything else I've used or can find.. 

Anyhow, just figured there was a bunch on here smarter than I and could help my mind process this..

Thanks!
 

Edited August 9, 2021 by sjlcjl

[sjlcjl 5]

I will follow up to my own question.. 
Over at the Roku forum, there is a lot of discussion about this problem..

So, this appears to be an issue with the 4800 series Roku's..  

Thanks anyhow, hopefully this may help someone else...

[speechles 2055]

The new Roku Express 4K+ (3941) has the same issue. I also have the Roku Ultra (4800) and it has the same problem. They are _ALWAYS_ in HDR whenever they are fed HEVC. Regardless what type SDR or HDR these Roku models will only show them in HDR. The HDR logo appears but it is SDR. This is clearly a bug on the Roku side of things.

https://community.roku.com/t5/Channel-Issues-Questions/Severe-color-contrast-distortion-while-Plex-streaming-HEVC-EAC3-videos/m-p/634403

The above thread has a similar complaint. You can open a new thread on the Roku forums to get them to address it. They may never reply but others with the similar issue will. Their forums are similar to how they are here. Eventually with enough support the Roku staff will reply.

There is presently no work-around for this issue (other than manually alter the header as you've found). It is something Roku must address on their end. Roku are supposed to eventually release an updated video player component that should correct the issue.

https://community.roku.com/t5/Playback-Issues-Audio-Video-Power/New-Roku-Ultra-2020-won-t-send-HDR-DolbyVision-signal-to-display/m-p/614992

There is also this which is the inverse problem. DolbyVision support is presently broken on these models.

 

Quote

problem solved,  for some odd reason the ultra 2020 has an "hdr always on" function buried in the advanced settings.  just switched it off, works fine now

AHA.. Because of poor HDR detection Roku does this. We must find the setting inside the Roku settings and disable.

Edited August 9, 2021 by speechles

[sjlcjl 5]

Hey there, thanks for the response..  That's the thread I ended up finding and saw that others were having the same issues..  

I'm the guy on the end of that thread that said to remove these items from the MKV header with MKVToolKit to resolve it for the time being..

Colour Matrix Coefficients
Colour Range
Transfer Characteristics
Colour Primaries

One question about it from the Emby side..  When I do "Playback Correction" within Emby, it resolves itself..  Not really sure what changes when it goes from Direct Play to Direct Stream..  
Maybe the simple fact that it's now HLS and it can't do HDR in that format or something...

 

 

 

[speechles 2055]

5 minutes ago, sjlcjl said:

Hey there, thanks for the response..  That's the thread I ended up finding and saw that others were having the same issues..  

I'm the guy on the end of that thread that said to remove these items from the MKV header with MKVToolKit to resolve it for the time being..

Colour Matrix Coefficients
Colour Range
Transfer Characteristics
Colour Primaries

One question about it from the Emby side..  When I do "Playback Correction" within Emby, it resolves itself..  Not really sure what changes when it goes from Direct Play to Direct Stream..  
Maybe the simple fact that it's now HLS and it can't do HDR in that format or something...

 

 

 

If it is direct playing using playback correction will change the container. That should correct the header problem and get it correct. But it is using ffmpeg to combine the streams into an m3u8 manifest with TS slices. It isn't CPU heavy. But it is a form of transcoding. It should show as DirectStream if both video and audio are copied. It will show Remux if the video is copied and audio is converted. It basically "simulates" an error has occured and closes the video player rudely just like an error. This forces our logic to try to recover playback using the next playback method. In most cases this correction will solve the problem. In some cases it might introduce new problems. It is a tool for users to solve playback issues without having to pull their hair out. You can use playback correction multiple times.

Edited August 9, 2021 by speechles

[sjlcjl 5]

Thanks again for the response.. 

Yeah, I've noticed when I use ffmpeg directly it doesn't add the header info flagging the file with BT.709 info and it works fine..  

Either way, removing that info from the header solves the problem regardless if it is HEVC/Whatever Audio..  

[Luke 42077]

That's interesting, thanks for reporting this to us.