This was the post I was thinking of.
How can we determine which profiles are supported by the device?
There’s TVs like Sony Android models that are known to only support single layer. Those TVs require an external UHD Blu-Ray player that can decode the dual layer content themselves since the TV can’t read that data directly passed to the TV.
But there are also TVs that should support directly passing dual layer.
As far as I know dual layer profile 5 content with a basic enhancement layer doesn’t require the playback device to decode but profile 5 content with a full enhancement layer does.
So how does Plex determine this?
Fully understand that Plex running on an external device like the shield can’t determine the profile level supported by the TV, but how can Plex determine which profile the shield itself sports?
With integrated smart platforms like Android TV, how can Plex know which profile is supported and how do users check it’s getting correctly handled by the TV?
@DaveBinM What if you use the Plex app for Android TV directly on your Z9D (like I am doing on my AG9/A9G). Can you still play Dolby Vision with profile 7?
I think you mostly have this right apart from the bit about the Oppo and MKV.
UHD Blu-Ray players that support Dolby Vision must support dual layer otherwise they wouldn’t be able to play back the discs. The difference with the Oppo 203 is it has a manual switch that controls either decoding the dual layer itself, or passing it to the TV.
It’s unclear how other UHD Blu-Ray players control this function, but they all should be capable of passing or decoding the data themselves. This is why there we’re initially problems with Sony TVs with devices like UHD Blu-Ray players, the devices needed to have decoding added to pass a new single layer profile to incompatible TVs.
How that detection mechanism works is probably via HDMI EDID, although I’m not certain with that.
Regarding MKV. There recently has been a change to the spec that allows dual layer data to successfully be ripped from UHD Blu-Ray’s without altering or converting the data to single layer. Anything you read about converting dual to single applies before this change. In effect, mirroring the disc itself. Plex now supports reading this format but it’s not clear how Plex determines what profile the playback device is capable of and how Plex behaves if it receives dual layer data on a playback device that only supporters single. That’s something I’ve asked about it my last reply and I really hope something Plex can answer.
Most people who post here seem to be using Plex with an Nvidia shield which as mentioned already in the thread poses it’s own set of problems. If the shield is capable of decoding dual layer data properly then there’s no way to control whether it does so or just passes HDR10 instead. Because of this limitation people can end up sending the wrong profile data to an unsupported TV, hence the remarks about it sometimes not working properly, or colors looking strange.
In particular those that are using a shield with Sony TVs that only accept profile 7 will probably be the ones with the most trouble.
But I digress, there needs to be some transparency and an explanation on how Plex determines profile support on a device by device basis so we can all understand where we stand. Things seem to work fine on my Hisense H9G with dual layer Dolby Vision MKV rips but without knowing the entire playback chain and exactly how Plex determines the TVs decoding capabilities we will never know if things are working as intended.
Of course such a simple toggle for the Shield would really help those who are connecting their device to a tv without full profile support. This goes for the Sony models that only support single layer, but also older models that have even more limited profile support… more toggles and the more complicated things become …
Of course the perfect solution would be what UHD Blu-Ray players must do, Nvidia need to add either a toggle like the Oppo 203 or some form of profile detection like other UHD Blu-Ray players.
And to top this all off, support on the Shield for dual layer Dolby Vision UHD Blu-Ray’s may just never work properly at all, unless Plex have some funky way of converting the signal if the Shield doesn’t support decoding dual layer data playback with always be broken.
So the rest is really down to Nvidia and whether they have the license or capability built in.
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Thanks for that answer 
Do you think m2ts hevc original file from UHD blu-ray with 2 layers can trigger DV?
I doubt it, there has to be various profile information contained in the data for software to interpret that data correctly and unless there has been some update to the file container spec like the recent changes to MKV then it won’t be able to carry this data. MKV is our shining light in the tunnel when it comes to even playing back these profile 7 dual layer dolby vision titles, but even so those that have devices that don’t support decoding profile 7 are still going to be in trouble.
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I’m not sure if devices really publicly document too much what profiles they support, so it’s hard to say. However, I’m quite confident that profile 5 is only single layer, at least from the last Dolby Vision specification document I read. Other profiles have multiple layers, but not profile 5.
We generally don’t need to detect exactly which profiles are supported, as we pass the data to the DOVI decoder on the device, and if it can decode it, then it does, otherwise, it should fall back to HDR10, for the profiles that support it. Otherwise, if you try to play something that doesn’t have a fallback to HDR10 (such as profile 5), then you may get some odd colours.
No, the DOVI decoder on the Z9D does not support profile 7. I’d need to go and review my testing notes, but I think it’s only profiles that streaming services like Disney+ or Netflix use that are supported directly on the TV.
In Plex? No, it won’t trigger it
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Thanks for clarification. So it’s safe to assume there won’t be any errors in processing if a non compatible profile is sent to a TV without support for that layer (eg profile 7 to Sony TV’s).
This is a good explanation of the profiles based on the official docs: https://avdisco.com/t/demystifying-dolby-vision-profile-levels-dolby-vision-levels-mel-fel/95
As you can see only profile 7 and 4 are dual layer. Profile 4 doesn’t seem to be used at all, whilst profile 7 is the type that people will want to use when playing back ripped UHD content in Plex.
But sadly it doesn’t end here. It’s possible to supply extra information added to profile 7 in the form of an enhancement layer. This info can either be ‘basic’ or ‘enhanced’. The former may well work on devices that don’t include dual layer decoders because no extra decoding is required, but the latter definitely needs to be decoded by a supported TV.
Of course this is just relevant when discussing support directly on a TV.
Is there a different strategy going to be used for dedicated players like the Google Chromecast TV or Nvidia shield? Is Plex going to simply pass the data to the connected TV for decoding (just the same as playing content directly on the TV) or can Plex function on these devices like player led UHD Blu-ray players do when connected to a TV without dual layer support?
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Yes, as long as there is a compatible profile is sent, then it should be okay. While profile 7 is what people get with content from 4K HDR BluRay discs, what gets created in the digital conversion process is a little different, and there is only one video stream, rather than two, which is what you get on a disc.
For dedicated players, like the Nvidia Shield or Google Chromecast with Google TV (what a longwinded name!), we already use the decoders on those devices, and then they pass along the data to the TV. So decoding is done on the playback device, then the device passes that to the TV/display. If you’re using the built in decoder on the TV (such as in the scenario you’re using a Sony Android TV, without another playback device), then you’re limited by what profiles that device supports in its DOVI decoder.
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So herein lays the golden question.
If someone owns a Sony TV, but also an Nvidia shield, will they be able to play back profile 7 content on the shield to be correctly passed to the TV? (Same as UHD Blu-ray players).
And what about other devices like Google Chromecast TV, Roku Ultra, Fire stick/cube. Do they decode profile 7 content okay?
I answered this in my previous reply, but yes, because the decoding is done on the playback device, which in this case would be an Nvidia Shield, and the TV is treated more like a display, rather than it doing decoding. As for all those other devices I don’t know exactly what profiles they support, so I can’t say for sure.
Ok, thanks for answering. Maybe it’s the same case with AG9/A9G. Netflix and Disney+ works with Dolby Vision, but I guess it’s profile 5. As mentioned earlier, profile 5 works with Plex as well.
I would suspect so. Things like this really come down to what the device makers support, unfortunately.
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I have a SHIELD 2019 and a LG CX OLED TV.
I can play single track dual layer Dolby Vision without issue.
I rip my BD with MakeMKV and MakeMKV muxes the 2 tracks into a single track (dual layer)
DV info: dvhe.07.06 BL+FEL+RPU (That’s DOVI Profile 7, DOVI level 6)
All the BD’s I have ripped has had either dvhe.07.06 BL+FEL+RPU or dvhe.07.06 BL+MEL+RPU
Plex play the files just fine and triggers Dolby Vision.
The only issue I have had is that TrueHD Atmos will often clip or dropout, making the atmos logo appear in the corner of the screen over and over again. If I playback with DTS-HD or Lossy Audio, there is no issue.
Plex server on a NUC, media on a synology NAS, gigabit network.
NOTES:
Make sure instant game responce is enabled on LG CX or Dolby Vision will not trigger.
LG HDMI Audio format must be “Bitstream”. If you switch to PCM Dolby Vision will not trigger.
To go further with this - MakeMKV 1.15.4 can convert previous rips of UHD dual-layer/dual-track files to dual-layer/single-track files.
This makes the Shield happier with the files, but doesn’t address some of the Shield’s color rendering issues.
And notably the streams are still Profile 7. This won’t help any Profile 5-only devices play them.
Converting to single-track has the small risk of hurting playback compatibility on some devices. The Blu-ray spec put the MEL/FEL on a separate track to maximize compatibility. I’m not aware of any known instances of this.
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What we need is a list of common TVs/devices and what profiles they are known to support (or known NOT to support).
Similar to the nas compatibility chart.
This would go a long way to help manage expectations.
Profiles are very rarely publicly documented, however, I don’t know if that’s a decision of Dolby, device manufacturers, or if it’s the case that they think the majority of people simply don’t need to know/care
Has anyone got a sample MKV I could try on my kit? Curious to know how it would handle it…
