Feature request: Support profile 7 Dolby Vision ('dual-layer DV') in MP4s

[TobyX]

First of all (especially to the mods): please read this topic carefully befor closing it (as a similiar topic was closed by one mod without any reasonable reason). Thank you

Second, for a better understanding, in the following, I will use terms like ‘single-’ vs. ‘dual-layer’ Dolby Vision (instead of the more uncommon tems profile 5 vs. profile 7 DV, respectively).

Some points before I start with some details about the present request
There is currently a discussion in another topic about the (new) Exoplayer (what also helps plex to support single-layer DV):

Latest Exoplayer?

Can plex please update the Exoplayer in the android app… Seems were still using v2.10.3 which is 6 months old.

The person who started this thread argued that currently, Plex does not use the newest version of the Exoplayer. Comming from another topic, I found out that a newer version would also support dual-layer DV.

Detect Dolby Vision profile 7

@anon18523487 argued that beside the fact that the (newer) Expoplayer supports DV, one cannot expect that Plex could play dual-layer DV (because of licensing). I was a bit confused about that.

So whats interesting/important to know about dual-layer Dolby Vision:
First of all, currently one get Dolby Vision only via Streaming Service (like Netflix) or from UHDs (or from UHDs ripps → MP4s with single- or dual-layer DV by using DVDFab).
Videos from streaming services with DV are single-layer DV streams. Videos from UHDs are usually dual-layer streams. There is a basic layer (HDR10) and an so-called enhencement layer which contains the important metadata for Dolby Vision. This is an important point hence it offers the highest compatibility with devices that do not support DV. In case of your setup does not support DV, the second (so-called enhencement layer) will be ignored and you will get HDR10 or HDR10+, respectively (a solely single-layer DV stream would lead to transcoding on your non-DV device due to the fact that there is no HDR10 base layer).

status quo:
To get Dolby Vision you will have to ripp your UHD. Currently, to my knowledge, only MP4 containers support DV (mkv does not support it) … there might be some other rather uncommon types. You will have to choose between single- and dual-layer DV at the beginning of the ripping procedure (e.g. using DVDFab).
Plex currently supports only single-layer DV.
@ChuckPa argued in a past topic that dual-layer Dolby Vision support in Plex is senseless because it would mean that we want to play physical media. Plex will not read Disks.
And here is a big misunderstanding. Unfortunatelly, I was not able to respond to this statement because Chuck instantly closed the topic.
To make it clear: Yes, usually dual-layer DV is only available on physical media (such as UHDs). However, you could also have dual-layer DV made from your ripps (mp4 files DV).
@TeknoJunky supports my suggestion that Chuck misunderstood my thoughts.
Taken from another topic:

@TeknoJunky

I don’t know why chuck closed that thread, the OP has nothing to do with plex reading the DISKS, but reading the EXTRACTED content which is exactly what chuck is proposing we should be doing.

So why not rely on sinlge-layer DV? Why should Plex also support dual-layer DV?
Here are some points

1. Compatibility: Dual-Layer DV mp4s are high compatible with devices that do not support DV at all. In such a case, Plex currently ignores the enhencement layer and plays HDR10, instead.

2. We do not really know how single-layer content is ripped by software like DVDFab: Interestingly, DVDFab, currently, seems to be the only way to get single-layer DV ripps from your media. Beside the fact that there is a great debate on how these guys got it work, there are some hints that DVDFab does not creat “real” single-layer DV. In the worst case, it only triggers the TV to show the Dolby Vision Sign on the screen. There is a guy who investigated the output of the single-layer DV stream comming from a ripp made by DVDFab and he argues that the enhencement layer has static metadata.Furhermore, single-layer DV from DVDFab is not in the correct colour space.
   Link (go to post by wesk05): Dolby Vision - Page 35 - MrMC

Accordingly, we should not rely on such an untransparent procedure what potentiallly generates not “real” single-layer DV.
Plex supports DV, yes, but only single-layer. But there is no benefit from that when there is only one tool what can generate single-layer DV ripps and, furthermore, it is totally not clear if the content is actually DV. Instead, Plex should support also dual-layer Dolby Vision hence it as the higher compatibility AND investigations showed that such content (mp4s generated from UHDs) is actually DV.