HDR Discussion Thread

[David M]

Originally Posted by PaulGo

From what I have read Blu-ray disks only support 8 bit color and currently only some sources such as Netflix 4K along with 4K HDR Blu-ray gives you 10 bit color so on a 10 bit TV how would the Dolby Vision 12 bit be of benefit?

Dolby Vision on UHD BD is 12-bit. The BDMV HDR base layer (now usually called HDR10) is 10-bit and the two extra bits are stored as a difference signal that can optionally be decoded on supported players. (They basically used the mechanism previously used for the Right-eye view on Blu-ray 3D). On a Dolby Vision setup decoding from the player is 12-bit.

Now, whether or not all those 12 bits make it out to your eyes via the display panel is another question, although that actually isn't critical. The important part is that all of the tone mapping and other HDR video processing is done at a high bit depth.

Supposedly, quite a lot of Dolby Vision titles are actually made from 10-bit masters though.

[Agent Kay]

Originally Posted by David M

Dolby Vision on UHD BD is 12-bit. The BDMV HDR base layer (now usually called HDR10) is 10-bit and the two extra bits are stored as a difference signal that can optionally be decoded on supported players. (They basically used the mechanism previously used for the Right-eye view on Blu-ray 3D). On a Dolby Vision setup decoding from the player is 12-bit.

Now, whether or not all those 12 bits make it out to your eyes via the display panel is another question, although that actually isn't critical. The important part is that all of the tone mapping and other HDR video processing is done at a high bit depth.

Supposedly, quite a lot of Dolby Vision titles are actually made from 10-bit masters though.

So the 10 bit master bit may be true then..

[RockyIII]

Is Oppo the only brand to support HDR10 to DV conversion?

[Penton-Man]

Follow-up news to the motion interpolation portion of this post from Sept. 9, 2018 – https://forum.blu-ray.com/showthread...n#post15506292

Yesterday, this article was posted online - https://www.slashfilm.com/war-on-motion-smoothing/.

[Penton-Man]

Originally Posted by Waboman

LordoftheRings is already sitting down at the table with her. Lordo, back in Montréal yet? Time to start practicing French or is that Quebecois or is that Frangalis? I am but a rookie at this linguistics stuff.

[Penton-Man]

Originally Posted by PaulGo

From what I have read Blu-ray disks only support 8 bit color and currently only some sources such as Netflix 4K along with 4K HDR Blu-ray gives you 10 bit color so on a 10 bit TV how would the Dolby Vision 12 bit be of benefit?

I see David already answered the UHD Blu-ray portion of your query above, so with regards to Netflix streaming, remember, Dolby Vision is natively 12-bit in the ICtCp color space. At encode, there is preprocessing and shaping into 10-bit HEVC for distribution and then it is mapped back to render a 12-bit ICtCp frame in a Dolby Vision enabled consumer 10-bit TV when viewing Dolby Vision streaming content. From there it gets tone mapped to the actual display's characteristics using dynamic metadata.

As I mentioned on the last page, which included one hyperlink to a previous post I made about ICtCp (but there are several others dating as far back as early 2016, e.g. https://forum.blu-ray.com/showthread...s#post11886102), introducing ICtCp, then following its progression thru JCT-VC for support in HEVC (https://forum.blu-ray.com/showthread...p#post12775898) and explaining in other posts along the way that I believe it is a superior color model for wide color gamut.

I expect ICtCp to be adopted with regards to other aspects in the future too.

[Penton-Man]

https://forum.blu-ray.com/showthread...n#post15361885
^ follow-up -> https://www.instagram.com/p/Bnb-WaFh...88829431159776

[Penton-Man]

https://forum.blu-ray.com/showthread...y#post15512898

Follow-up -
Saturday night is already sold out - https://www.ticketweb.com/event/top-...ickets/8645515
Friday night, still available – https://www.ticketweb.com/event/top-...ickets/8645495

[Penton-Man]

Originally Posted by LordoftheRings

Cool video Penton, I like it.

I like this one too(scroll down a little)....
https://www.dolby.com/us/en/about/dolby-cares.html

[Geoff D]

Originally Posted by Agent Kay

So the 10 bit master bit may be true then..

I always figured that plenty of stuff was 10-bit simply because it was locked in at that bit depth in the DI mastering and/or the rendering e.g. CG animated movies, and even now content is still being finished at 10-bit. So yeah, the encode itself may be 12-bit but that isn't a guarantee of the source being 12-bit. And the metadata-only DV enhancement layers that we've seen on several UHD discs so far would also bear that out, that there's literally nothing else in the DV layer to append to the base layer, merely upsampling it to 12-bit upon playback and adding in the dynamic metadata.

[Agent Kay]

Originally Posted by Geoff D

I always figured that plenty of stuff was 10-bit simply because it was locked in at that bit depth in the DI mastering and/or the rendering e.g. CG animated movies, and even now content is still being finished at 10-bit. So yeah, the encode itself may be 12-bit but that isn't a guarantee of the source being 12-bit. And the metadata-only DV enhancement layers that we've seen on several UHD discs so far would also bear that out, that there's literally nothing else in the DV layer to append to the base layer, merely upsampling it to 12-bit upon playback and adding in the dynamic metadata.

Yeah, I was thinking the same.

[LordoftheRings]

It feels real good to know that Dolby cares. We all care.

[mrtickleuk]

Originally Posted by RockyIII

Is Oppo the only brand to support HDR10 to DV conversion?

Conversion? I know that it can package up a HDR10 signal into a DV signal, but I'm not sure if there's any meaningly "conversion" happening. How would it even work?

[RockyIII]

Originally Posted by mrtickleuk

Conversion? I know that it can package up a HDR10 signal into a DV signal, but I'm not sure if there's any meaningly "conversion" happening. How would it even work?

Maybe I used the wrong word. Oppo can take a HDR10-only disc and play it back in DV, yes?

[DanBa]

Yes.

As far as I understand, the dynamic metadata are the input parameters for the Dolby Vision Display Management performing the tone and gamut mapping.
Without the input parameters, the Display Management uses the default parameters.

[RockyIII]

And is Oppo the only one that is currently doing that?

[Penton-Man]

Originally Posted by LordoftheRings

It feels real good to know that Dolby cares. We all care.

well, some make an effort to do so

[Penton-Man]

Originally Posted by Geoff D

I always figured that plenty of stuff was 10-bit simply because it was locked in at that bit depth in the DI mastering and/or the rendering...

It’s more complex than this outline –



In the last step of Dolby Vision color grading, the post production facility typically creates a UHD Dolby Vision mezzanine master (MXF 12-Bit RGB JPEG2000 file + an XML) and OTT content creators like Netflix, etc. like to have it then formatted into an IMF file (depending on the frame rate either IMF Main Level 7, Sub-level 4 or IMF Main Level 6, Sub-level 3 (see p.7 - https://drive.google.com/file/d/0B37...5sMzNwcmc/view )

after which the mastering operator runs it thru a 2nd party encoder like a Dolby Vision supported Beamr encoder - https://beamr.com/vanguard-by-beamr-...hevc-codec-sdk and from that Dolby Vision IMF master, the home deliverable files are derived. As per my post above about UHD HDR streaming content, even though the transport into peoples’ homes is 10-bit HEVC, the 12-bit ICtCp mastering fidelity is maintained.

[Penton-Man]

^ P.S.
Some smaller Dolby certified post house facilities and forward thinking indie filmmakers are hoping that someday Dolby offers their own budget Dolby Vision encoder to allow them to then take the mezzanine master, run it thru that Dolby Vision encoding device which would then generate a home deliverable file that the operator can play on some Dolby Vision supported consumer TV for Q/A and testing purposes of their content because the smaller outfits just don’t do enough Dolby Vision production to invest in expensive 2nd party Dolby Vision supported encoders and view the final step in the process.

[LordoftheRings]

Originally Posted by Penton-Man

well, some make an effort to do so

Oh, I missed some action. I was sure I was on AVS forum reading those, spooky.
_____

https://www.youtube.com/watch?v=HA0t...ature=youtu.be