I’ve noticed that some 4K HDR content plays fine on all Plex clients (ATV 4K, Safari/Chrome, etc), with the correct tone mapping and no issues. However, other HDR content will play with incorrect tone mapping producing green and purple images. This happens on 4K HDR TVs as well. Does anyone have any idea why this would be happening? Is the issue Dolby Vision? If so, is there any word on when this will be available on Plex? Equipment being used listed below:
@ChuckPa I think I forgot to @ you in my last comment about this. Just wondering if there’s any more information about what development has decided on doing. This is jamming us up
Profile 5 (DV only) support in AppleTV Plex client is coming/should be available now.
Transcoding DV to SDR isn’t ready (not certain as to if/when they will have it)
Regarding the OPs post,
I have a LG C1 (2021) model which will play all Dolby Vision natively in the Plex app. Where the troubles occur – is when subtitles exist in the file.
Image based subtitles , or anything the TV itself can’t handle, will force the transcoding.
The moment the video is transcoded – Dolby Vision breaks because you’re getting H.264 SDR tone mapped video output (which doesn’t yet account for DV). Without the HDR-compatibility layer in the file – you get wonky colors.
I conducted several tests. In every test where subtitles needed transcoding, it broke.
The point I will make here –
Please curate your media carefully.
Only include subtitles if you need them. Remove (remux) then out if not.
I’ll gladly put together a few screenshots on how to do this if needed.
Thank you @ChuckPa . That is good news about apple TV but I am still seeing the purple/green with my Shield Pro. I ended up switching my apple tv 4K out because the apple TV was not able to pass through the TrueHD audio. So it seems that the users of the Plex video player can either chose between playable DOVI videos, or trueHD audio pass through. To my knowledge, there is no way to achieve both. Tough situation.
@ChuckPa 1. Does your equipment natively have any support for TrueHD or DoVi ?
My sound equipment is able to decode Atmos/TrueHD, which I can pass through the Shield, pass through the TV, directly to the receiver. That is working right.
The screen does not support DOVI, it is a 2021 Samsung screen. So, when I encounter a profile 5 file, it shows up purple and green. I could go get a new TV that can decode DOVI, and have considered doing that. However I still get purple on my PC screen, etc. To eradicate the issue from my home i’d need to replace several different monitors and tv screens.
In principal I agree with you about just avoiding the DOVI profile 5 files. Don’t try to play DOVI (profile 5) files on a non DOVI screen easy right? However, having the option to play DOVI files on a non DOVI screen is an enhancement request that would keep my tv and many others out of the landfill. Or from switching to a player that can map the colors somehow.
If not, Why would you consider having DoVi/TrueHD content if you can’t enjoy it in its native form?
I believe that some of the content is only available in Dovi Profile 5. And that is an increasingly common format. I could avoid it, but then I wouldn’t get to watch some shows and movies that we really like.
Profile 5 is a streaming-only profile. It has no HDR-compatibility layer. This is why, when transcoded (which needs HDR base) its colors are wonky. It was never meant to be captured (Web rips) – which was deliberate on their part.
The team is aware and understanding of the need.
AppleTV 4K can/will so be able to play profile 5 videos.
Transcoding (which includes mapping) profile 5 videos to generate a SDR-base is being considered/worked on. I don’t know more than that.
For it to work, you MUST have HDCP 2.2-capable cabling. HDCP 1.4 will not suffice. I went with the 48 Ghz cabling and am somewhat future-proof there as that also supports the EARC return channel.
Samsung is trying to split the industry here. They have created HDR10+ (their version of HDR10 DV). My new LG cannot play HDR10+ (Samsung-only) content. Since all the discs I rip have that base HDR 10 layer, I’m OK because that’s all I need. I don’t need Samsung’s variant of “DV”.
I think, in the long run, Samsung is going to lose this battle. The industry is entrenched with Dolby.
My connections are as follows;
Shield Pro 2019 (Shield Experience 9.0) → Onkyo AVR
Apple TV (2017) → Onkyo AVR
Onkyo breaks out the audio and processes locally to my Polk speakers.
Onkyo then forwards the video stream (also HDCP 2.2) to the LG C1.
If you have a sound bar instead of an AVR, you’ll connect Shield Pro → TV → Soundbar.
My video content is all from discs which I own. These are profile 6 or 7 (mostly) and do include the HDR base. This is why I have no issues when transcoding and tone mapping down to a lower bit rate for Remote Access use.
@ChuckPa I appreciate the insights. Am somewhat surprised to hear you are successfully getting TrueHD audio out of your apple tv, to the receiver. That’s why I got rid of my apple tv, because I determined that was impossible - guess I was wrong on that!
Thank you also for the info on the transcoding to work around profile 5. I will hope it works out, sounds like the issue and pain is well understood. As well as the solution.
Sounds like there is hope. Do you have any advice on how to keep up to date with progress/changes on this as more info becomes available?
Please don’t misunderstand the AppleTV audio capabilities.
AppleTV 4K will decode EVERYTHING above core 5.1 to PCM (lossless). You’ll get lossless audio but you won’t get the Indicator on your receiver/soundbar. AFAIK, the reason they stop there is entirely licensing (a Steve Jobs holdover) and not letting Dolby have access to Apple’s source code.
The Shield Pro will pass through the audio to the receiver completely intact.
(we worked with Nvidia when Shield Experience 8.2 was in development to get it all working). Here, AFAIK, the Nvidia team completely reverse-engineered their solution based on the published specifications.
As for keeping up to date, I can only advise watching the release announcements (apps and server).
I don’t usually know until a few days before launch.
@ChuckPa So you are saying, that ATV decoding to and outputting PCM bitstream will result in the same exact audio in a 11.1.4 Atmos sound system as the Nvidia shield pro pass through? The only difference is that the label won’t display on the audio system? The apple tv PCM bistream maintains all of the Atmos spatial data, and other artifacts other than the label?
If this is all true, I might go get my apple tv back…
No, decoding to a lossless PCM bitstream will preserve the “core” audio (up to 7.1), but positional audio (Atmos, DTS:X) that uses height or presence information (aka the “.4” in your question) will be lost. To keep that, you must have a player that support bitstream passthrough to the receiver, such as Shield, or Xbox.
If you have a TV that supports Dolby Vision (eg, LG OLED), Receiver that supports Dolby Atmos and DV passthrough (eg most 2017+ models), Plex Client Video Quality set to “Original”:
Nvidia Shield Pro (2019 version), Xbox (and possibly other clients I’m missing): Dolby P5 will DirectPlay with correct colors, audio will be decoded correctly by the receiver.
AppleTV: Very recent versions of the AppleTV client attempt to DirectPlay the DV video through the original ATV media player thus preserving the color, but it seems there are still issues/bugs with this. Atmos audio will be converted do 7.1 core audio.
(most every other client): Video will be transcoded (with incorrect colors), audio will be converted to 5.1.
If you don’t have a TV that supports DolbyVision, Xbox may still correctly play DolbyVision P5 content (ie show correct colors), but everything else will show it incorrectly I think? Also if Transcoding is needed for any reason on any client (Quality level setting is bandwidth limited, or file has PGS subtitles, etc), then the DV file will have the wrong colors during transcode.
@millercentral Alright I’m going to get a Dolby Vision TV. Even IF the transcoding feature gets implemented (profile 5->SDR) it’s still not going to be great. Viewing the DV profile 5 in it’s native format is ideal. And since this format is increasingly common, it makes sense to get rid of this Samsung. What a waste
While I don’t have any 11.1.4 content to test with, the 7.1.2 content I do have does indeed come through to the receiver (Onkyo TX-RZ) as PCM from the ATV 4K 2017.
I can’t guarantee every receiver will know what to do with 7.1.2 or higher PCM; I know my Onkyo processed it correctly.
When I played with the Shield, I got the same sound PLUS the nice little indicator.
So I am entering dangerous territory here as my experience is @ChuckPa is much smarter than I am…
My question to you would be: “What audio processing mode is set for your receiver on your plex input?” I’m guessing you have a mode like (the confusingly named) “Dolby Surround” mode enabled that takes a traditional multichannel audio source and “upscales” it to use all the spatial audio presence speakers available on your system. While this will still sound great, it is not exactly the same thing as the actual Atmos bitstream. Atmos (and DTS:X) spatial audio is not sent as “discrete” channels in quite the same way as core multichannel audio is. Instead it is a set of metadata that provides positional information for sound in 3D space, that the AV Receiver then translates to your room based on where the speakers in your system are located.
If you were to set your receiver decode mode to “Straight Through” I think you would see the difference between “Multichannel PCM” and a device that can bitstream passthru the native Atmos audio stream.
The player sets its Output mode and sends the signals.
The receiver takes that input.
The receiver decodes the input and, based on the speakers you have and soundstage setting you selected, postprocesses the signals and send them to your speakers the best way it can.
The postprocessing soundstage is what the dial you see on your receiver is for. (DTS:X, etc). It will postprocess the decoded signals to provide artificial effects.
For my postprocessing, I select select “Direct” and let the signals come out to my speakers as intended. For some receivers, this is the ‘Flat’ soundstage setting.
At this point, the only thing impeding quality of reproductdion are the speakers themselves and their placement.
My Onkyo has a calibration microphone so it knows the exact distance to each speaker from that microphone.
By placing the microphone where I sit, It computes the digital delays required to make certain I get the exact audio ‘image’ presented to my ears.
I will be deemed a purist by many but who am I to overrule how the recording / audio engineers want the movie to sound?
