How to detect Dolby Vision in a videofile?

[d3rd3vil]

Ladies and gentlemen,

the issue at hand is about Dolby Vision :)

Does anyone have an idea how to detect DV in a videofile? For example MediaInfo doesnt seem to have the appropriate info whether DV is in the file or not.

For example this TS Dolby Vision file right here:
https://drive.google.com/uc?export=download&id=0Bxj6TUyM3NwjQ0RDWVVsWUtRMnM

Dolby Vision works. Tested on an LG Oled with DV capability.
After throwing the TS file in MKVToolNix the MediaInfo is quite similar however DV doesnt work anymore on my tv, its gone or deactivated or whatever. The metadata seems to get lost.

So is there a way to see DV in the TS file to see the difference between the TS and the mkvtoolnix mkv?

Thank you very much in advance

I know DV is still very new and in the early stages more or less. But maybe some of you have an idea for the issue at hand :)
Waiting for PowerDVD for example is possible of course but it will take months I suppose...

[Balwyn]

Have no explanation for you, however replicated your results with my LG OLED TV, so nothing wrong with your test method.

[kolak]

As far as I know DV data is inside h265 headers and it's dynamically inserted per scene. It's quite complicated and you can look at x265 documentation to see how it's done. There is some section about it.


update: sorry, I was talking about HDR10+, but DV is about the same.

[d3rd3vil]

We need professionals the real Dolby Vision gods to solve the problem someday. We need the good stuff :)

[kolak]

Not sure what you mean. Dolby won't give you anything for free- it's very patenting/money orientated company.

[raffriff42]

https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-white-paper.pdf
Yep, from the looks of this, they really want to lock it down. Gonna require a secret decoder ring, er chip, no doubt...
https://www.dropbox.com/s/cwjvwloxvn2uqvl/Dolby%20Vision%20white-paper9a.png?raw=1

[Blue_MiSfit]

This dual stream technique is not used in practice AFAIK.

Real Dolby Vision implementations (I forget the profile numbers) for OTT VOD are pure 10 bit HEVC with proprietary dynamic metadata stored in SEI messages.

[nevcairiel]

This dual stream technique is not used in practice AFAIK.

On Blu-ray it is.

[benwaggoner]

On Blu-ray it is.
Correct. Although I don't know that it is actually required for discs.

And I have heard at least one streaming provider is currently using dual layer. The single layer is quite a bit more bitrate efficient, so the general trend is to use that instead, But dual layer was available a lot earlier, so that's what a lot of early tooling was built around.

[benwaggoner]

As far as I know DV data is inside h265 headers and it's dynamically inserted per scene. It's quite complicated and you can look at x265 documentation to see how it's done. There is some section about it.

update: sorry, I was talking about HDR10+, but DV is about the same.
They are actually WAY different.

The single layer Dolby Vision uses a non-backwards compatible HEVC 10-bit base layer, using ICtCp and dynamically adjusting so that the 10 bits of precision are mapped to the current video parameters to preserve more precision. The file is absolutely not playable in a general HEVC player; it needs a lot of metadata-driven Dolby algorithms to convert from the non-backwards compatible stream to Dolby's 12-bit ICtCp space, and then using other metadata to go from that to the display, optimizing for the display's characteristics.

HDR10+ is a HDR-10 base layer, plus metadata in the SEI that can be used to improve tone mapping, or ignored. So those streams are playable in themselves in any HDR-10 capable player.

Dolby has a big proprietary display tone mapping library. HDR10+ is really just the descriptive metadata; it's up to each vendor to figure out how to use that metadata in their own tone mappers.

[SeeMoreDigital]

Well....

When my Oppo UDP-203 plays typical HDR video sources, the player produces the following info: -
Media Information
HDR Format: BDMV HDR
Colour space: BT2020 YCbCr 4:2:0 @ 10-bit

HDMI(Main) Output Information
HDR Format: HDR
Colour Space: BT2020 YCbCr 4:2:2 @ 12-bit

But when playing Dolby Vision sources, my Oppo produces the following info: -
Media Information
HDR Format: Dolby Vision
Colour space: Dolby Vision @ 12-bit

HDMI(Main) Output Information
HDR Format: Dolby Vision
Colour Space: Dolby Vision @ 12-bit

So somehow a 4:2:0 10-bit (not 12-bit) encoded video stream becomes a uniquely flagged 'Dolby Vision' 12-bit output...

[d3rd3vil]

Well there are 2 things that could be interesting.

1: A software mediaplayer that can play DV material. That will probably be tricky.

2. A way to convert all the relevant data to mkvs or ts formats so the TV can handle the rest and play it.
And the second option should be easier to accomplish?! Of course there are already ts DV files that are no prob for the tv.

[benwaggoner]

Well....

When my Oppo UDP-203 plays typical HDR video sources, the player produces the following info: -
Media Information
HDR Format: BDMV HDR
Colour space: BT2020 YCbCr 4:2:0 @ 10-bit

HDMI(Main) Output Information
HDR Format: HDR
Colour Space: BT2020 YCbCr 4:2:2 @ 12-bit

But when playing Dolby Vision sources, my Oppo produces the following info: -
Media Information
HDR Format: Dolby Vision
Colour space: Dolby Vision @ 12-bit

HDMI(Main) Output Information
HDR Format: Dolby Vision
Colour Space: Dolby Vision @ 12-bit

So somehow a 4:2:0 10-bit (not 12-bit) encoded video stream becomes a uniquely flagged 'Dolby Vision' 12-bit output...
DoVi even has a mode to pack pixels into RGB 8-bit over HDMI 1.4 (the technology predates HDMI 2.0). There are several HDMI modes, which different devices might call different things. And older receiver should be able to pass through the weird modes without knowing they are DoVi.

[SeeMoreDigital]

I wonder if it's possible to find some 'repeat information' with a hex editor...

[d3rd3vil]

Why is there no real detection software out yet? And also no mediaplayer for PC that can play the stuff....I dont believe it. Damn it Dolby

[SeeMoreDigital]

Jeez... There's less than two dozen UHD discs currently available (and most of them arn't worth watching). What's the rush?

[d3rd3vil]

No real rush but it looks like we'll have to wait till 2018 at least which is a bit disappointing.

[hajj_3]

mediainfo was updated today, there is something in the changelog about HDR detection, might want to give that a try.

[d3rd3vil]

Nope nothing worth mentioning

[d3rd3vil]

Anyone working on a reverse-engineering of Dolby Vision yet? ^^ For MediaInfo, or TSMuxxer, or sth. else, anything :)

[d3rd3vil]

So is there sth. new or is it still all a mystery? Can only god and religions help us here?

[kolak]

There seems to be some documentation here:

https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-for-creative-professionals.html

[Blue_MiSfit]

Looks hopeful?

https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-bitstreams-within-the-iso-base-media-file-format-v2.0.pdf
https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-bitstreams-within-the-mpeg-2-transport-stream-format-v1.1.pdf
https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-streams-within-the-mpeg-dash-format-v1.1.pdf
https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-streams-within-the-http-live-streaming-format-v1.1.pdf

[d3rd3vil]

Ah finally some knowledge behind the DV implementation :)

[nevcairiel]

These docs are barely helpful. You might be able to figure out if Dolby Vision is present in a given stream, but there is absolutely nothing in there to help decoding it.

[d3rd3vil]

Man damn shit :( Its too late anyway. HDR10+ will soon come and even THEN we wont be able to play or decode DV....HDR10+ it is then

[kolak]

These docs are barely helpful. You might be able to figure out if Dolby Vision is present in a given stream, but there is absolutely nothing in there to help decoding it.

Don't expect to see anything public as DV is very proprietary and protected format. Dolby loves their patents etc. Atm. there are only few facilities which can create DV masters ( and only few products which support DV exports).
Same with decoding- only after signing agreement with Dolby you can get access to format specifics.

[benwaggoner]

Man damn shit :( Its too late anyway. HDR10+ will soon come and even THEN we wont be able to play or decode DV....HDR10+ it is then
The value proposition of HDR10+ and DoVi have significant differences. HDR10+ doesn't specify how the metadata gets used. Dolby certifies DoVi implementations as accurately displaying their content.

No technical reason why the Dolby Vision playback libraries couldn't support HDR10+, for example

[Grencola]

If there was only a way to download https://www.scenarist.com/index.php/ateme-titan-landing/ it would be able to do everything with dolby vision we need :/

[nevcairiel]

You would be able to create DoVi files with that, playback is still another matter entirely. :)

Actually, decoding the DoVi metadata is probably not even that hard, its basically a second video stream where the "pixels" are an extra layer of HDR info, and I have seen some documentation on that. So just split it off and decode it. However, interpreting and using that "raw" data is another matter entirely.

[benwaggoner]

And MediaInfo 17.12 says it can read Dolby Vision metadata. I haven't tried it yet.

https://mediaarea.net/MediaInfo/ChangeLog

+ Dolby Vision: detection of Dolby Vision and display of profile for MPEG-TS and MP4 files

[SeeMoreDigital]

And MediaInfo 17.12 says it can read Dolby Vision metadata. I haven't tried it yet.

https://mediaarea.net/MediaInfo/ChangeLog

+ Dolby Vision: detection of Dolby Vision and display of profile for MPEG-TS and MP4 filesIndeed it can. Here's an example: -

General
ID : 1 (0x1)
Complete name : E:\UHD HDR Test Files\DolbyVision\LG Dolby Trailer 4K Demo [with flag].ts
Format : MPEG-TS
File size : 308 MiB
Duration : 1 min 20 s
Overall bit rate mode : Constant
Overall bit rate : 31.9 Mb/s

Video
ID : 33 (0x21)
Menu ID : 2 (0x2)
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5@Main
Dolby Vision : 1.0, dvhe.dtr@uhd24, BL+EL+RPU
Codec ID : 36
Duration : 1 min 19 s
Bit rate : 29.6 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.149
Stream size : 282 MiB (92%)

Audio
ID : 35 (0x23)
Menu ID : 2 (0x2)
Format : E-AC-3
Format/Info : Enhanced Audio Coding 3
Codec ID : 135
Duration : 1 min 20 s
Bit rate mode : Constant
Bit rate : 768 kb/s
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 kHz
Frame rate : 187.500 FPS (256 SPF)
Compression mode : Lossy
Delay relative to video : -948 ms
Stream size : 7.41 MiB (2%)
Service kind : Complete Main

[Grencola]

You would be able to create DoVi files with that, playback is still another matter entirely.

The current version of MrMC on Apple TV, as well as the USB port of LG OLEDs and possibly other TVs can playback single layer Dolby Vision files (tested using LG DV Demo .ts file). The problem is that there aren't any single layer DV movies, since UHD Blurays use dual layer Dolby Vision, but with Ateme Titan software you could properly mux the Metadata right onto the main .m2ts and create a playable single layer file :)

[kolak]

If there was only a way to download https://www.scenarist.com/index.php/ateme-titan-landing/ it would be able to do everything with dolby vision we need :/


Are you going to produce DV content with this knowledge or use it to decode "5" existing titles?
At the moment creating HDR10 or HDR10+ is complex enough.

[Grencola]

Are you going to produce DV content with this knowledge or use it to decode "5" existing titles?
At the moment creating HDR10 or HDR10+ is complex enough.


First of all, there are almost 40 UHD Blurays with Dolby Vision out already: http://www.nextgenhometheater.com/dolby-vision-uhd-blu-ray-movies/ so it's best to get with the times man :p

Second of all, I don't need to decode anything, I'd simply mux any dual layer Dolby Vision movie into a single layer DV .ts file that current software is waiting patiently to play (see above).

I've tried using TSMuxer, and although it does detect the DV Metadata and creates a single .ts output file, Media Info still shows that the second Dolby Vision video track is along side the main video track. We need to actually encode the DV layer right onto the main layer so it's a single layer profile like the LG Demo in order to play properly. No other software I've found but Ateme Titan seems capable of doing this. The majority of UHD Discs are created using Titan in the first place :)

The only way to currently watch dual layer DV UHD BD Backups is with an Oppo udp-203 (via USB hdd or burn physical discs). And since it's insanely expensive, it would sure be nice to be able to cater to the rest of the community ;)

[kolak]

40 titles is exactly what counts as "5" :)
It's tiny number.

I'm not sure if you can do it this way.
As far as I understand you decide about 1 layer v. 2 layers on h265 encoding stage based on your case (BD or stream etc).
It's not as easy as taking 2 layers and muxing into 1 layer- you would need to do re-encoding in this case.
1 layer v. 2 layers are not compatible between each other.
You need to decode 2 layers into "final" DV stream and then encode this as new 1 layer h265. 2nd layer (or part of it) of 2 layers stream has to end up in actual video stream ("as video" not metadata) of 1 layer, so re-muxing won't do it.
I may be wrong, but don't think I'm wrong.

Other than this UHD BD is almost dead. After good start, momentum was lost and part of it is because tools are expensive (also studios paying poor money for authoring) and there are almost no independent authoring studios doing UHD BD projects. There is no money in authoring business anymore. You have in reality few companies world wide which are able to do UHD BD (they are all big boys operating on "factory style work", eg. Technicolor, Deluxe etc). Other issue is that many companies lost interests in physical media and there is no one to "drive it". Big studio still release as for them it's making money on the same content just sold in "other form", but at some point it may stop being profitable and end up a niche product, like eg. DVD-Audio was. UHD BD is still the best quality format which end consumer can get and I think this is the main driving power (but streaming is getting better and better).

[d3rd3vil]

Yep thats exactly it. We need ts files for the TV to play properly. m2ts doesnt work.
If someone can get this to work then god bless him. m2ts to ts properly.

UHD BD is dead? Wtf do you mean ^^ Its STARTING thats whats happening we are in the golden UHD Bluray age :)

Und wie man sehen kann, zeigt MediaInfo natürlich keinerlei DV Daten an.

[kolak]

You can't convert dual layer DV streams found on UHD BD discs into single layer (playable by TVs) without re-encoding. This can't be done without knowing core of DV format, which is not public and never will be (until reverse engineered).
Atm. DV is very unique format and only tiny number of facilities world wide have technology which allows to create it.

It started quite a time ago with "good start", but current reality is not so shiny.
I know what I'm talking as I have access to this world from "behind the scenes" :) I know facts which you don't have idea about as end consumer (not someone who use to work in this industry).

[d3rd3vil]

Yes I understand so we are entirely fucked

[Grencola]

Well, thanks for your insight. I clearly didn't quite realize the process involved, I knew encoding was necessary and figured Ateme Titan could do this conversion of dual layer to single layer based on this:

"TITAN supports the widest range of input formats, media containers and video codecs, and can transcode any kind of mezzanine file into multiple outputs such as HEVC main and main 10 profiles up to level 5.2, Dolby Vision profile for 4K Ultra HD, H.264, MP4/MPEG-2 TS for VOD/push-VOD services, or Apple®’s HTTP Live Streaming and Microsoft®’s Smooth Streaming for OTT delivery as well as author-ready SDR/HDR elementary streams for Ultra HD Blu-ray."

Since it can transcode a UHD BD DV profile into a selection of Dolby Vision UHD profiles (the one used for streaming is single layer), I thought that would do the trick :/

Also UHD BD might be on the decline, I won't debate that as you seem to have inside information that I do not, but every week more and more titles are being released. And since they're the best quality version you can find I think it's worth looking into as there's a huge community of people who own DV TV's that would love a lossless UHD collection.

[kolak]

There will be more releases as big studio wants to make money, but reality is that compared to DVD era, today you have many ways of delivering content to home users and UHD BD will represent just a small portion of the whole market.
If you're mainly interested in mainstream Hollywood titles (which today are mainly crap) then this should be still coming. For smaller distributors UHD BD (+HDR) is just very expensive and not worth a try.
Even if suddenly there would be need to author 10000 titles there would be no resources do it (fairly quickly) as only small number of facilities do UHD authoring.
The faster internet gets the bigger shift will be towards streaming. I still prefer 10x quality of Blu-ray than Netflix, but at some point it won't be so different. Physical content still will be with us for many years (DVD is still doing well), but its proportion of the whole market will be shrinking every year.

[kolak]

Since it can transcode a UHD BD DV profile into a selection of Dolby Vision UHD profiles (the one used for streaming is single layer), I thought that would do the trick :/
.

Nope- this is done from high quality master+XML DV metadata.
As I said- you would have to decode DV dual layer stream back into "master"+metadata and encode back to single layer profile.
There is probably no commercial tool to do it (except Dolby SDK). Dolby would also never want you to do such a workaround as quality would be affected.

[Grencola]

Well this is heart-breaking :( I guess I'll wait until it gets reverse-engineered, but I won't hold my breath. Thanks for the replies!

[d3rd3vil]

The dolby guys are assholes anyway. Ok who wants to reverse engineer the good stuff?

[kolak]

You are dreaming here...

[d3rd3vil]

Well of course I am. We can only get DV in our dreams thats for sure

[Blue_MiSfit]

The Dolby engineers are actually great folks. Maybe not super open-source friendly when it comes to their IP, that's for sure ;)

[d3rd3vil]

Any news ladies and gentlemen?

[kolak]

No, you have to keep dreaming :)

[richardpl]

Anybody going to provide with dolby vision samples?